I am kind of in the same situation as you, except that I have 10 years before I retire. I have been researching living full time in a class a motor home for about 4 months now. I find that the more questions I find the answers to the more questions I have. All I can say is RESEARCH, RESEARCH, RESEARCH. I would like a 35' to 40' class a, some people have said that that size is far to big for one person, but that's what I feel comfortable in. Go to RV shows and dealerships in your area. I live in Clearwater, FL there are numerous large dealerships very close to me. My budget as of now is in the $50,000 range, but who knows if I win the lottery, that would all change.
Good luck to you! I know I can't wait to retire and head on down the road.