Ok, short version sold the house and went full time, did all the research set up a mail service etc, The DMV is not wanting to take it for my tag renewal. They need a physical residence within the co...
A mail service simply gives you a box, a Personal Mail Box, PMB. You couldn't reside in that PMB, so that address isn't a "real" residential address.
Some such as Escapees and St. Brendan's Isle can provide you a real address that you could live at, a domicile address. You would also become a legal resident of Texas or Florida for better or worse.