You are wise to be asking your question. I'm only 66. So, I'm just getting started. It is all about the individual. Some 79 year olds should have quit RVing years ago, but I've met many RVers well into their 80s that are still going strong if not a little slower.
You'll only get opinions here from caring fellow RVers. I would ask my neighbors, doctor, children and grand children your questions. They have personal first hand experience with your physical and mental state. Then, you have to listen to their advice.
Good luck and safe travels.