Like Valhalla360 stated, domicile can be difficult to establish and, as you apparently know, NY does not let go easily. If you don't plan on being in NY more that 180 days each year, there's nothing wrong with establishing domicile elsewhere. Keep in mind owning real estate, even in NY, does not by itself make one a resident at that location.
A good source is the Escapees site and forums, and they have a well-established mailing service for those who choose SD, TX, or FL. As a FL resident, I can tell you the state is well-prepared to handle non full-time residents, what with the big numbers of snowbirds and RV'ers. It might even be worth a trip to FL to sell the existing RV and purchase new in FL, and establish domicile at the same time.