We are retired and live just south of Houston, Texas. We bought a mobile home in a RV park in Harlingen TX (south Texas) in November to use as a get away home. We have been very pleased with both the park and the climate. Property taxes are very reasonable and our electricity is provided by an electric coop which makes it also reasonable. You might want to try several different areas to see if you are compatible with weather, medical facilities, and people and then make a decision to pick the one you like best. Many of the RV parks have excellent activities for park residents. Don't just jump in and buy the first place you see. Often after the peak of "winter texans" the prices of different facilities drop. If you have any friends at a particular area talk to them about the pros and cons of the area.
We have a son in Arizona, but for us the temperature is too extreme.