I have osteo arthritis everywhere including my spine.
Is a TC a ridiculous choice? And NO, I do not want to sleep on the dinette.
My wife(67) also has osteo in her spine and we just sold a small class C and went back to the truck camper.We both enjoy the option of being able to go where most RV's can't and park in a normal parking spot. We're almost 100% boondocker's in the mountains of Idaho. She's like a little monkey getting into the bunk her way, without issue. I'm sure when you find what one you want, you can try getting on and off the top bunk and see how it works for you. There's all sorts of options for steps or ladders if that helps.