I suspect that I am about your physical equivalent. 71 yrs, little strength and less stamina. I get around on the ground with a little PMV, little red scooter. I can walk, depending upon which day it is, anywhere from 10' to a block on a good day. No way could I hitch up a trailer. Also, I need a place to stop and rest, on occasion. Car or pickup doesn't get it, for that. My bed or the couch does it fine. My wife is similarlly challenged. Both are AF Vets, disabled.
I love my class A, and wouldn't be without it. Well, unless I win the lottery and upgrade to a bigger one. It is a 36' Damon Challenger. We have just finished up outfitting it for towing our new Suzuki XL-7 toad. I can handle the hookups, for that. We have motorhomed for four years, now, the last as members here on The RV Forum Community.
This forum is the most important "upgrade" we have made. It changed RVing from "just possible," to "almost easy," from "super expensive" to "fairly expensive" but manageable. Stay with the Forum and keep us posted. Got a question - any question - post it here. You'll be addicted to this place in short order.
I had a life long friend who was on oxygen for several years. He traveled with a couple of small oxygen cylinders and a concentrator. I think he refilled his bottles from the concentrator. In any case, he did not need to stop and get refills, when traveling. I don't use oxygen and don't know exactly how he did it. He passed away in December, so I can't ask him. He did love to travel and did a lot of it.
When we are driving, we usually run our generator for 110, while on the road. Mostly, that is for airconditioning comfort. It adds very little to gas consumption, so why be without it? You could do that, for your concentrator, when not on shore power. Don't worry about hours on the genset, as it is good for it to run it. Far as I know, they last forever.
So, my advice, get a nice class A, that you like, and move on down the road. You can most likely handle the hookups for a toad, as well. Live it up and enjoy! Do what you can, while you can. Go where you always wanted to go.
Ray D