I would start by putting together your own criteria matrix and then rating different areas. Medical is one thing to consider and some states are actively supporting Obamacare and others have governors that are indifferent or even hostile to the idea that people in the USA should be able to get medical care at the level that is common across Scandinavia, Canada, and Europe.
Weather is also a consideration in terms of year round comfort, access to outdoor activities, and utility heating and cooling bills. RV's are, except for a few 5th wheel trailers, not well insulated at all.
I would want to be where there are plenty of activities available within an hour drive time. I did two years in Dallas, TX where it was 1400 miles to the nearest mountains and nearly as far to get to the ocean and the lakes were all man made reservoirs with scrub brush around them. For out of town visitors there was no place to go and nothing to go see. Now I live in Monterey which is the exact opposite in almost every respect.
As one "ages in place" this becomes even more important as well as the availability of mass transit. Also access to an international airport is important to us as we love to travel outside the USA.
I have also found that with my travels around the USA that there are 50 different "states of mind" and how people treat "outsiders" or people of color, or a different religion in terms of tolerance and acceptance varies considerably. Not a big deal when doing a business trip or just passing through but something I take to heart in terms of spending time in an area.
The lack of cultural diversity in an area also makes the food very boring if you eat at the restaurants. If you do not eat out or love the food at the Cracker Barrel then this is not important.
You are wise to be thinking about getting out of Florida. All the gulf states are going to get harder as a result of the environmental degradation caused by the oil companies and these are the states that are also doing nothing to prepare for the next Katrina/Sandy event.
Cost of living numbers are not something to rely upon as they include the cost of buying or renting a house and the cost of property taxes and average incomes and other factors that are not relevant to retirees in an RV.
In some areas there are RV communities whereby you buy a lot with a large garage for the RV and an adjoining building that is a small 1-2 bedroom house with a kitchen and laundry room. These function as a rest stop before heading out for your next trip.
Out in the west water is something to consider if settling into an area. Many communities are running out of water at this time and many more will run out in the years ahead as ground water sources are depleted.
We spend our free time kayaking, fishing, bicycling, hiking, taking photographs, and similar activities and there are few places that compare to California for year round fun outdoors. If I was a hard core fisherman then the San Diego would be appealing.
Lots of excellent Web sources for climate data so you can see how many days of sunshine, how many inches of rain, average high and low temperatures, by month of the year and decide if the climate in a particular area is in line with your wants. We for example never want to live anywhere that an air conditioner is important. On that note, Hawaii is exceptional in that most of the houses lack an air conditioner and don't have a furnace either - think about it.