Pick your 'domicile' state......set up a mail forwarding address so that you have a 'physical' address to use for drivers license, vehicle registration, insurance etc.
Then you can get all your change of address done.
Go to that 'domicile' state....stay the required amount of time to establish your 'residency' and go get new drivers licenses.register your vehicle with your new physical address.
South Dakota is very Full Time RVr friendly. Only have to stay one might to become a resident. Course you have to go back every 5 yrs. to renew DLs...but they were (maybe have) changing to a on-line renewal.
Low sales tax, low insurance costs....no state income tax
FL & TX are other RV friendly states...........but SD was the cheapest for us.