For context, I only rented twice, about ten years ago (at retirement) for national parks touring, once from Cruise America (Class C), and once from El Monte (Class A). My husband did all the driving and hook-ups. Both times we took his old, but relatively healthy parents.
Both companies and their vehicles performed flawlessly.
One trip we flew to Salt Lake City, and did a circular tour of the national parks in the southwest. The other was a cross-country tour, flew to Orlando, flew back from Las Vegas.
If you are flexible and looking to save money, both companies offer fleet relocation specials, where you essentially do them the favor of moving the RV, for drastically reduced cost.
The beauty of the RV rental was constant comfort and convenience. The importance of this is proportional to the remoteness of your travel. You always have the food you prefer, whenever it suits you. You always can rest, sleep, or potty break. It is a home on wheels. Then you roll all that convenience right up to your destination. And as odd as it seems to the uninitiated, a stop of a few hours at Walmart, or a truck stop, is an excellent way to recharge yourself en-route to your destination.
For someone like you describe yourself as, retirement age with medical concerns, it give you independence to bring what you need, anywhere, anytime.
Caveat: I recommend that you be a skilled and attentive driver, as most RV's are longer, wider, and taller than anything most people have tackled before. Besides the obvious physical obstacles that presents, high winds can fling you about.
Regarding the need for a dinghy (towed vehicle), we never needed one. Most campgrounds have a camp store, and we changed locations every day or two, so we just used the RV for everything. Usually, at the end of the day, we were too tired to need a dinghy for anything.
Good luck, and happy trails.
