What an adventure! It's beyond my means to go as they are so I target what I can do.
For my needs, I'd step up to an F-350 4x4 and use up to a 10 foot TC with perhaps a single slide so I don't have to mess with a superhitch. I will be adding another 140 watts of solar soon. We are setup very nicely for the camping we like to do which is dissapear for a week or so somewhere away from it all and unplug, relax, and see the sights. If all works out according to plan, we may take a trip swinging down to Nevada, Utah, New Mexico, to see the Grand Canyon, Bryce Canyon, Hover Dam, Ride the scenic Railroad north of Santa Fe. Perhaps visit my brother in Lostwages, NV and whatever else I want to do in a 16 day period.
I thnk everyone has an idea of what it takes to make them comforatable, and hence what "will do".
Honestly, I believe there are a group of folks that are willing to not be comfortable. Or they are comfortable with not being comfortable. I know some folks that are so tight with their money they squeak when they walk and they would definitely rather be uncomfortable than spend the money to be comfortable.
I think everyone has a different idea of comfortable.
I am personally comfortable with a sleeping bag that is appropriate for the weather, ground cloth, and clothes and food in a backpack. I do mean truely comfortable. So anything above and beyond that is luxury to me.
DW on the other hand is not. Our kids will take it either way.
I am not trying to knock the bigger is better concept, as that is what some are comfortable with.
It takes all kinds of people, or there would be one model of camper and that is it.
I'll have to fully agree with Sabconsulting. I think Sab (Steve) had put his thoughts contextualized in a world-view: geographically/spatially/sociologically shaped.
I'll add that if your geographic, urban landscape and social context RVing happens to be Europe, you'll most likely have the Swiss couple's world-view: a compact RV rig with high amenity-to-service accouterments (i.e. highly efficient equipment).
*the statistical outliers to the above may be Europeans who expedition through the African Continent, Mongolia, and other expansive locales, requiring large expedition vehicles that can carry hundreds of gallons of water, food and fuel
Now, Europeans who RV overseas (like to the USA specifically) will rent a large North American-sized Class C on arrival.
*the statistical outliers are the Europeans who export their compact Euro-campers over here, with either right-hand or left-hand drive; even rarer, Europeans who export their large Mann/Unimog systems over here (a tiny cohort of the former segment).
Now, North Americans who RV in Europe usually want to export their larger truck camper rigs to Europe as a first thought, but usually down-size to a European-sized RV on further investigation.
*the statistical outlier are North Americans who actually do export their large rigs to Europe, and perhaps regret it later, for many negative operational and spatial reasons
Concluding, the answer is very complex, and no one simple theory can explain fully every RVers decision to go one way or another...
The smallest that will do is traveling with the clothes on your back and perhaps a small backpack.
The idea is the smallest that will do with an ACCEPTABLE LEVEL OF COMFORT. You could argure that pre-historic humans lived with nothing but a loin cloth and if that makes you happy and they don't lock you up in the loony bin, good for you but that is taking it to an absurd level.
What constitutes acceptable comfort varies by person, so you can't just say this is the correct rig for everyone.
When you start talking about 40' monster rigs with every available ammenity, most of those rigs were chossen with the bigger is better mentality (a few maybe not but those would be rare examples).
Tammy Mike & the Bilge Rat (AKA: Diego)
Ford F250 7.3L
1997 Sunnybrook 27' 5er
1995 Gemini Sail Catamaran 34'
Full Time spliting time between boat and 5er