We tow a 2000 Jeep TJ Sahara. Transfer case in neutral auto tranny in park, key turned to first position to unlock steering and away you go. I can't even tell its back there when towing. A good 4x4 will extend your exploring capabilities.
I have a 98 Country Coach Diesel pusher. I never owned a gaser. I do like how quiet it is having the engine in the back. As for maintenance, my Cummins holds 7 gallons of oil, the oil filter is huge, I have 2 fuel filters, a large air filter and a coolant filter. So the basic maintenance is going to cost more but the longevity of the Engine and Tranny is well worth it. I have the Allison 3060 Tranny, I had the fluid and filters changed at an Allison Shop and when I was leaving they said see you in 300,000 miles. That tells a story right there. For the larger and heavier class A coaches you can't beat a diesel. They are built to run, built to work and built to last. Why is it you don't find gas engines in 18 wheelers.
I flat tow my 2000 Jeep TJ and love it. As for the difficulty for older people getting in and out of the back seat. The fix is to have younger friends and keep the older people out of the jeep. Just kidding, It can be a small challenge getting in and out but the jeep experience will have their adrenalin flowing so there should be no difficulty.