I coated my motorhome with a EPDM coating, and it was fairly easy to install. I don't think I would want to spend the $4,000 that was quoted on a new EPDM roof on my RV, it is a 1996, and I do not want to sink that kind of money into it.. .
If I make it to 79, I will not be using a fifth wheel! Those look to difficult to hook up when I get older. Why not trade to a class B van, or widebody van, smaller class C or something?
Your reaction time is not what it used to be, and backing a small van is a lot easier than backing up the truck and fifth wheel combo. Stopping a 14,000 pound class C or 10,000 pound van is much easier than the truck and trailer combo.
I know - you are only as old as you feel. My grandfather sold his home in California in 1964 and moved back to Arkansas to live. At the age of 80, (1969) he said "I would not give up this place for all of California!" He really enjoyed it! He stopped driving at age of 94, and lived to 99! There is something to be said about the stress free life of living in a small rural town!
Somehow in another 30 years, I will not be feeling like hooking up a fifth wheel to a tuck and taking it anyplace, but the class C or smaller class B might be just the ticket!
Good luck, and enjoy the ride! You only go around once!
Fred.