SD, TX and FL are common states RV FTrs use as a 'domicile' state.
Each has their good/not so good qualities. Different for each persons needs.
Ins., medical coverage, estate taxes, vehicle registrations, voting, concealed carry permits, etc.
Establishing 'residency' is easy......just need a mail forwarding service so that you have a physical address, then stay one night...go get drivers license, register vehicles, register to vote. Just have to have all the correct documentation to get drivers license.
We use SD as our 'domicile' and our vehicle insurance rates are lower than TX or FL
We use National Interstate Ins. for coverage. We have a 'full timers' policy (same type of coverage that we had on our S&B Home) and they cover our truck also. Been with them for 7 yrs. Their rates were cheaper than other quotes.
We have had two claims....one minor and one major. Both claims handled quick, efficiently with NO hassles or increase in premiums.
You can set up your 'physical address' on-line and get all your mail addresses changed over..then go to the state and get DLs etc.
Lots of mail forwarding services in all 3 states.....they all seem to do a good job. Haven't heard bad about any of them.