Sorry to hear about your back issues. Wish you well.
I'm sure it goes without saying, but I would go think through things methodically to anticipate the potential trouble spots. You hopefully know your limitations and therefore can see where the issues might be. For instance, I would think the biggest problems would be handling the weight distribution hitch and sway bars. Hopefully you have help getting them installed before you go, if not, what can you do to help minimize the trouble with these. I posted a WDH storage caddie made from a harbor freight rolling mechanics seat about a week ago. I only have minimal periodic back strain issues but I hated having to lug that hitch around and store it. While traveling we leave the WDH on the truck. The sway bars are a different issue. Will they be a problem to lift? If so, you will need to come up with a way to handle this since they can't easily be left attached. Anyway, walk through every step you can think of and look for the "hot" spots and devise a way to deal with them.
A class C might be easier in some respects, but it will bring challenges of its own. If you don't tow a car, you will have to break camp or Uber every time you need to go somewhere. If you tow a car, it brings its own weight challenges. Leveling a class C without automatic jacks adds two more tires to level vs a TT, etc...
Good luck and happy camping!