One of the most complex issues we face as RV'ers will always be 'residency', in part due to vehicle fees and sales taxes and in part due to state income tax.
It seems to me the best way to address this issue is asking RV.net for the different applications in states depending if your retired, working, and where you spend the most time.
Once you collect that background info, and verify it, then contact an attorney in the state you choose and verify it again. Once you make this choice for state residency, it's generally expensive the first time - that is, buy and register a vehicle, plates and tags, license fees, mail changes - all the things that document your residence.
Why 'move' twice because you didn't do your homework first? And, you always need the long-range plan expenses. That fact that you save money on sales tax buying a vehicle is only one factor, and can easily be offset by other factors if you 'forget one' that applies annually instead of sale tax.
There's a very good web page that lists ALL retirement impacts with a different state on it each month. Next time, I'll copy that link here, and you all can find any state in its back-log. It has a page for each state and all the taxes, fees, retirement issues, etc separately. So it's easy to pick one or two or three and compare those factors that apply to your personal situation.