I've seen some special adjustable driver's seats in shuttle buses and school buses built on E-350, E-450 and Chevy express chassis. I don't know if any of these are spring base, or if they are just more adjustable and possibly better built than the seats RV manufacturers buy.
I've also been in a few shuttles where the driver's seat looks like an OEM piece, so for the companies that make these buses either some don't install special seats or they are an option. But in any case, if shuttle and school bus manufacturers are installing special seats, somebody out there makes them.
Maybe one of the manufacturers of these Type A school buses can give you a lead to a driver's seat supplier. School bus manufacturers include Bluebird (Microbird subsidy), Thomas, Collins, Starcraft, and Transtech. Starcraft is also a leading manufacturer of shuttles, small transit buses, executive transports, party buses and so on, so they are likely to have a lot of connections to interior furnishing suppliers. Starcraft Bus is a Forest River company (one of their five bus companies). Don't look for Starcraft at Thor, they use the name for RVs only (someone else owns it for boats) but Thor may also own a transit bus company or two.
Knoedler makes a suspension seat for the Sprinter, Extreme Low Rider, for about $1700-1800; I don't know if this would adapt to the E-series. This manufacturer shows other models for RV applications, but these might be for Class A motorhomes, which have a different driving position.
B motorhomes (van conversions) built on Transit, Sprinter and Ram Promaster do not really have frames, they are unibody.
When built as cab-chassis or cutaway, as used for a "B+", C, or box truck, Sprinter and Transit cabs are put on a conventional rail frame, while the front-drive Promaster (essentially a Fiat Ducato adapted to North America) gets a special RV chassis behind the cab.
E-series and Express/Savannah vans from GM are/were body on frame. The cab-chassis and cutaway versions, dually at least, get beefed up suspension components and options for longer wheelbase than used with the van bodies. The E-350 and E-450 are also sold as bare frames, used for panel vans and some lightweight Class A motorhomes. M-B sells a dually 3500 series Sprinter bare chassis for this market as well.
The F-53/F-59 are bare chassis in Class 5 and Class 6 weight ratings (16,000 to 24,000 pounds). They are used today to make Class A gas motorhomes in North America, as well as being the platform for some specialty vehicles like rolling offices, bookmobiles, mobile medical units, mobile command posts, etc.
I've not heard of a need for a steering stabilizer on the Transit or Sprinter cab-chassis. Some people find a stabilizer or centering device useful with the E-series cutaway chassis. The F-53 has a steering stabilizer as OEM, but some customers replace that with aftermarket or a centering device, and also make other chassis modifications that may improve ride or handling, or make driving easier.
I would not expect handling problems for RVs the size of the Gemini. Unlike larger C's, these have not been extended beyond the design size of the chassis, although they are likely close to maximum weight ratings when loaded for travel.
Transit, over the years, has been well proven as a platform in the European small motorhome market (which is substantially larger than ours). Earlier generations of the Transit cab-chassis owned about 50% of the type C RV chassis market in much of Europe for a while, although Italian coachbuilders preferred FIAT's Ducato and French coachbuilders preferred Renault's Master or the Peugeot/Citroen versions of the Ducato.
This changed with the introduction of the 3rd generation FIAT Ducato/Peugeot Boxer/Citroen Jumper in 2006. The small motorhome market in Europe (i.e. within a 3.5 tonne weight limit) was ready for a modern front wheel drive chassis (front drive allows more room for the house and a lower profile) and the Ducato/Boxer/Jumper moved up to 80+% market share.
The Sprinter in Europe, since introduction of a high capacity bare chassis, has been popular as a platform for larger motorhomes, up to 5 tonne weight class. These are what we call Class A, and most of the manufacture is in Germany, where the buyers are.
Since the introduction of the 3rd generation Renault Master and 4th generation Ford Transit, the Ducato's market share has been shrinking. The Transit and Master are available front drive with ratings up to 3.5 tonnes to compete with Ducato and VW's T5 in the smaller van category, and as rear-drive or all wheel drive to compete with MB-Sprinter and VW Crafter in the market for heavier vans.
Tonne is English long ton, or metric ton, 1000 KG.
I travel a lot in places where the traffic moving over the speed limit (which might be 75 or 80 mph out here on the plains) is a whole lot faster than my gas RV comfortably manages, so on these high speed highways I try to keep up with the heavy trucks in the right lane, and if they want to go past me, they can take their chances on the passing lane where someone might be coming along at 100 MPH.
Actual speeds, if I have no wind or a decent tail wind, my cruise speed might be as high as 70-75 mph not towing, 60-65 mph towing. Into a 15-20 mph headwind, or bucking strong crosswinds, I might be down to 55-65 mph on rural highways.
For me, it is about adjusting to conditions. If it was about "best MPG" I would have to cruise at 35-45 MPH which would not be safe on highways, not legal on most limited access highways, and not very useful for making progress on a road trip.
You have to find your own MPH niche, and it will vary with conditions.
For me, it was worth what I paid. I was there in October, first thing in the morning, and it was not crowded. I've also paid to see Lookout Mountain. I paid to ride through the gorge late in the afternoon before, and a camping fee to be around to see the gorge from the top in the morning.
But it depends on your interests, and how you value your money. Most of these attractions cost less than a decent bottle of wine or a six pack of good beer. To some folks that is a lot of money, to others it is trivial. It tend to rather value these attractions not vs the entry fees but rather the time I spent there, and Royal Gorge for me was worth the time spent. Consider that I am a geologist, and have particular interests you may not share. For me, Legoland or Six Flags Anywhere is a waste of time and money, a special geological feature is not.
Best guide I've found, and I've bought several, is "EZ66 Guide for Travelers" by Jerry McClanahan, published by the National Historic Route 66 Federation. It covers various vintages of Route 66 (routing changed over the 30+ years it was so designated) and helps you find historic relics long abandoned.
"Historic Route 66" markers through Oklahoma mostly put you on what is left of the last routing before US-66 was decommissioned. There is a lot of useful mileage of this vintage, as I-44 (routed onto the Will Rogers and Turner turnpikes) did not replace US-66, rather bypassed the old roads.
You might be tempted to get onto expressways to go through Tulsa or Oklahoma City (you will have to to get across the Arkansas River) but following the later routings through town can be worthwhile, although 66 did not go through OKC, it goes through Edmund, to the north. In Tulsa, the historical markers take you across 11th Street, where you will find Talley's Diner at 11th and Yale, a 50's style venue that was not really there in the 50's. However, I'm not sure where you would park a motorhome, it is hard enough finding parking for a minivan in that area, particularly when the classic car guys or bikers are gathering at Talleys.
I used to prefer the Metro Diner on 11th, but the University of Tulsa bought the property and tore it down to build dormitories. Presence of a growing university community makes this a high-rent district, and is also why parking is hard to find.
I used to have a favorite lunch stop in Stroud, but I think the property has been turned into an upscale bar, kind of like an unfranchised Hard Rock Cafe.
With a really good guide, stopping at all the attractions, seeking out the old bridges and byways, it could take you a week to get from Joplin to Oklahoma City, nominally 3 1/2 hours on the turnpikes. Turner Turnpike was built to cut the Tulsa-OKC travel time by half, and with the Will Rogers it pays for the whole state turnpike system, as all the other segments don't have the traffic to pay for upkeep.
While it goes much better before 6 AM on a Sunday, most of the time I hit this stretch of I-80/I-90/I-94 between 10 AM and 2 PM. Traffic is typically heavy and moving at or above speed limits, from I-55 to Portage (or Benton Harbor if you are going on into Michigan). Driving can be intense, because traffic is moving fast.
There are other times of day that congestion from commuter traffic will slow things to a crawl (and all it takes is one stupid move causing an accident).
For what it is worth, you do not go through Chicago on I-80, this is the bypass. I-88 and I-90 go through, and those are a lot more pain. I know, I lived on the north side for several years and had to go out east and west often.
Going into Michigan, I-94 from Portage to Benton Harbor is a lot more crazy, with traffic speeds from just under the speed limit to over 100 mph. I settle into the right lane to move with the big trucks.
Doesn't have much to do with RVing, really. It is more about economics and time constraints.
When I was time-constrained, I would do a trip with 10-15 hours driving time in one day. Once I retired, that would be at least two days, or three, or four, exploring along the way. My nieces and nephews still do Michigan to Florida or Michigan to Outer Banks as a non-stop trip. If they want to visit California they fly.
Once retired and making seasonal moves, with months at the destination, the picture changes. My cousin has summer property in northern Michigan, winters in his RV in South Florida about six months. It is still 12-14 hours of driving, he will take a week or two to make the trip. When he was 30 and had to get back to his job, he would do it in one day.
You father-in-law is concerned about the economics of it, he got paid for miles, not for time. The kids have limited vacation time and want to maximize time at destination.
You need to stop worrying about what other people think about what your are doing. Different folks have different needs, which lead them to different uses of their time.
One more example, my wife and I, when she was still living, liked long days at sea, so we did a few positioning cruises, and round trips from the mainland to Pacific Islands. This means seven to ten "sea days" for one to two weeks at destination ports. If you have the time, this is nice, but if you have one week or two weeks for your vacation, you get to the destination as quickly as possible.
LPG conversions were fairly common before the days of port fuel injection. They were easiest were in the carburetor era, replacing the carb with a LPG throttle body injection piece.
There are firms today doing dual-fuel conversions, either CNG or LPG with gasoline on modern fuel injection vehicles (mostly medium duty trucks, which fall outside a lot of EPA restrictions that apply to lighter vehicles). Cost of a dual fuel conversions is typically in the $6000 to $15,000 range (it is a whole lot less as a factory option).
Your gas motorhome is built on a bare medium duty truck chassis. It is a matter for finding a supplier for the conversion and working out a price.
I would consider rigging up fishnet across the opening of their bunk. The stuff used to be sold in hobby and "import deco" stores as decorative material.
Many years of camping, this was never a problem with younger siblings, children, or grandchildren in my family. The young ones knew where they slept, once they were told, and pretty much stayed there. If it is not a problem at home, it shouldn't be a problem camping.
Where are you going?
New Jersey and Oregon are 50 feet max. Kentucky, Maryland and West Virginia are 55 feet. Alabama, Connecticut, Delaware, Florida, Illinois, Indiana, Iowa, Massachusetts, North Carolina, Rhode Island, and Virginia set the length limit to 60 feet. Most of the rest of the states are 65 feet, assumed to be a Federal standard for the Interstate and designated highway system, but you sometimes have to get off those roads. A few states go to 70 or 75 feet, which applies to the Federal system in that state.
In states with limits more restrictive than the 65 feet standard for designated Federal highways, you are often allowed some off-highway access, one to three miles. This is mostly to allow commercial truck access to terminals and service destinations, but RV destinations might be that close as well.
You can usually buy a permit to go longer (we must move around wind machine parts, oil field service rigs and ICBMs from time to time) but oversize loads are restricted to specific routes and often require escort. Some states go beyond 100 feet on designated highways with commercial permit yet unescorted (they boost combined weight limits as well) but these are options not useful for a RV you want to take anywhere.
I would target 65 feet overall and be prepared to drop my tow where the limits are more restrictive.
Small towns in rural areas of the middle of the country (Appalachians to Sierra Nevada) have been no problem. Cities and suburbs are more of a problem, I am mostly looking for relatively empty parking lots, street parking seldom works and urban parking places are sized for SUVs at the largest.
After a couple of tours this past year in the East (I-95 corridor from Maine to D.C.) I would say finding parking for a 30-foot anything anywhere could be a problem. I haven't been with the RV to the urbanized West Coast, but suspect that parking would be a challenge.
If you are really planning on regularly driving in snow and mud, Michelin makes the lugged tread XPS Traction in the 215/85R16 size, same capacity but slightly taller. I'm not sure anyone else has an all-steel commercial-grade traction tire in a size that fits. If you choose a traction tire for the rear, you would probably still want a steering tire like R250 or XPS Rib for the front.
When I upgraded from consumer all-season tires to commercial all-steel, I put on XPS Rib tires all around on my C, with the idea that I would never take the RV into winter conditions. XPS Rib is a summer tire with rubber compounds addressing durability rather than wet traction, let alone staying soft enough to deal with icy roads.
I also have a one-ton van that uses the same tire size and load rating. This one I need to take anywhere anytime, so I run all-season tires on that one (currently Michelin LTX M/S2). The way this van is typically used, I feel no need for the retreadability and heavier tread of commercial all-steel tires, so I'm OK with all-season Michelin LTX, Goodyear Wranglers, Firestone Transforce, knowing that I'll be replacing them early, i.e. when tread depths get halfway to "minimum" if going into seasons of heavy rain.
If I lived in the Great Lakes area or the Dakotas, I would probably use something like the LTX Winter year round, rather than the LTX M/S2. Although it is the same tread pattern, the rubber compound is more suitable for ice traction. At the other end of the scale, the Defender LTX has a more wear resistant tread than the LTX M/S2, with some compromises in wet traction.
Where you live, I would not compromise on wet traction. I would still intend to not be RVing in ice and snow. That's when it is time to move south.
I know some people who have been doing this in Airstreams, some of them for as long as 50 years. I see full timers also in old aluminum Holiday Ramblers, and aluminum framed TTs from Carriage. There are also folks still using 50 year old Shastas. I expect any well-made travel trailer can stand up to years of constant use, with regular preventive maintenance, but it will be easier with something built better (often heavier) to start with. That would likely not be the one with the lowest price.
All the places I've visited or lived over the past 70 years, RV or no RV. Before my wife died it was the places we've been together, but now it is my map, not our map.
Which reminds me, I need to update the map in my signature, if I can remember where I made the image.
I don't know which show you are watching, but the ones I've seen have been portable gas burners. Fuel comes from a small can of butane (hidden in the base), ratings range 8,000-15,000 BTU per burner. The burners are surprisingly cheap, fuel a bit more than $1 per 8 oz can, from online restaurant suppliers.
Search on Chef Master (two words) for one vendor. For the camping market Coleman sells a single burner butane table top (in addition to their LPG and liquid fuel ranges), and Camp Chef sells 1 and 2 burner butane tabletop models.
LPG models tend to be more popular for camping because a 1 pound bottle of propane can generate more gas (up to 60,000 btu/hr) than a small can of butane, i.e. enough for 2 to 4 burners. Multi-burner butane stoves use a can of butane to feed each burner.
I use and old liquid-fuel Coleman converted to LPG, which has even higher output on a single burner than most LPG stoves because there is more flow capacity at the burner.
I've also seen the use of electric hot plates and tabletop induction units, these are plugged in somewhere, you just don't see the cord.
RMNP and Estes don't even make my top 10. Most of my favorites are in southern Colorado.
1. Grand Junction, Colorado National Monument
2. Gunnison Valley: Montrose, Black Canyon NP, Curecanti NRA, Blue Mesa Reservoir.
3. Cortez to Durango to Silverton, including Mesa Verde NP
4. Upper Arkansas valley, Canon City to Poncha Springs.
I've done it several times, usually in my pickup or full-size van, but once with 30-foot C. I'm always going south on 59 (my northbound routes are different, it is a time of day thing) so can't advise on connections northbound.
The route through Atchison is not too bad. I've side tripped a couple of times there to visit the Amelia Earhart Birthplace museum, which is not too bad with a smaller vehicle, but you can get trapped in that neighborhood with a RV.
South side of St Joseph can be slow going, particularly the Lake Avenue section, which is a busy residential-light industrial section with narrow old rough streets and diagonal three-way to five-way intersections.
Once you get on US-36 it is four-lane divided (but not controlled access) all the way to the Mississippi River, with traffic lights only in Cameron around the I-35 junction.
Be sure to check with DOT in Kansas and Missouri. I've been caught a couple of times by road closings between Atchison and St Joe, and forced to do some backtracking.