If you are close, see if you can find out where the fresh water tank is. If it is behind the axles, traveling with a full tank will (slightly) reduce pin weight. If it is in front of the axles, any water will make it worse.
Apple (at the apple store) changed both batteries in my iphone 5's for free. If your phone calls within a certain serial number spread, they change it free. My wifes phone had the battery swollen, they replaced the phone free - I just had to go home to back it up, then back to the apple store for a replacement. Go to a store, and ask them to check the serial number to see if it qualifies for free replacement. It looks like apple for a bad batch of batteries nov/dec of 2012..
I have had good luck with the Goodyear G614 tires, 3750 # @ 110 PSI. Rated for all positions, steer, drive, tag and trailer.
I can't fine anywhere that they are rated other then trailer. Where did you see this?
Generators loose power as altitude goes up. A 2k will start most AC's at sea level, a 3k most anywhere reasonable. 10,000 to 15,000 foot mountain peaks aren't what most consider reasonable as far as AC's. They usually aren't needed and even a 3k with a hard start cap on the ac will struggle.
Most high output aftermarket alternators are close to 50% output at idle, VS closer to 20% for small stock alternators.
The stock Ford 130 amp alternator in our E450 motorhome's V10 chassis puts out 60-70 amps when the engine is idling, according to Ford's published alternator performance curve for it. This is around the 50% point for the alternator.
I have a permanent ammeter installed in our motorhome and with the engine idling I have seen the alternator dump over 50 amps into the coach battery bank when the batteries have been discharged down to around 50% state of charge. We don't have solar on the RV so often when the batteries get low, I hit them with the idling engine and it's alternator for up to an hour before firing up the little portable generator to finish the charging.
I would not consider 130 amps small, I was referring to the 60-80 ish amp units that with the heater and lights on, rev the engine and the lights get brighter and the fan speeds up.
There are several examples of off grid people mounting a gas engine (think riding lawnmower size) to a high output alternator. They (usually) call them DC generators. Assuming fusing at BOTH ends, go for it. I ran 4/0 for my inverter charger - both ways.
Most high output aftermarket alternators are close to 50% output at idle, VS closer to 20% for small stock alternators. I think the 16 HP figure is a bit high, 10hp at full output seems more reasonable. The AC compressor pulls a significant load on the engine and cooling system, with no ill effect (other then mpg's).
The solar is a good idea, but 500 watts at 14.4 volts is a whopping 34.7 amps theoretical max at the panels, real world closer to 25-30 amps at the batteries, less if it is overcast.
When will it be above freezing where you are? Wrapping the sewer hose in heat tape & foam insulation may help. Once you have water flow in the sewer line again, take a HOT shower in the trailer and let the water drain, the extra heat should help melt more of the ice in the line.
There are 12 volt electric heating pads, intended for tanks, ultra heat pad. These are intended for water / waste tanks, and are to large to leave on full time. A relay on the furnace blower, to power the tank heater when the rv's heater is on can solve that. Some sort of quick disconnect on each tank so you can remove them for filling, and you are done.
Why is it? People look for absolute minimum tool for the job at hand! Money.
For the cost of ANY 3/4 ton + the Kelderman air ride, it is cheaper to do it right the first time and get the right tool. In this case a dually.
Trailers gain weight with age, what is slightly under the max on your first trip, will be hundreds over in a few years. Get something big enough for 3 years from now.
Try not to run much off the starting batteries, If the truck doesn't start, your problems are.
I would look at "auxiliary under vehicle battery mount" if you must run things off the truck. Add a battery or three for the freezer, with an isolator or even a second alternator to charge them. If you are running them down in a day or two, a generator based charger is needed as well.
How many batteries are on the trailer, maybe adding another one (to get less depth of discharge) and run it there is a better option.
Bumper pull trailers tend to be about 10-12% pin weight, 5ers are 20-25%, empty toy haulers are 25-30%. In most cases you will run out of rear axle weight long before you hit gvwr on a SRW truck. A 10k TT can easily be pulled by a 3/4 truck, a 15k 5er is at or above the rear axle limit on almost all srw trucks. Remember, you are not delivering the trailer, you are putting stuff in it, and in the cab of your truck, then hauling it. Between a hitch in the bed, a passenger up front, and a little carry on luggage, you can eat 500 lbs of the gvwr before the trailer is ever attached, and the 100 or so lbs of the hitch is directly on the rear axle.
Do not put rollers on a RV! All you will end up doing is making the frame flex more, and at some point cause the sidewalls to be damaged. It was build to be supported at one end and the middle. The wheels will be supporting it at both ends, not what you want on something this long and heavy.
First check the equalizers, and see if there is an adjustment. Are you currently towing it nose high? If so, adjust the pinbox / 5th wheel to level it. Lippert makes a product called Correct Track. It is intended to correct the alignment of the axles, and it also lifts the trailer as a side effect. Something to look into if you are having wear issues as well. The other options are taller tires (doesn't gain more then and inch usually). An axle flip (puts the axles under the springs VS above them - lifts the rig the thickness of the axle + the spring pack. A sub frame, usually a square made of box tubing, remove the spring mounts equalizer mount, attach the metal box where they were, and reinstall all the mounts where they were - now under the subframe. you end up lifting the trailer the height of the subframe .