I'm not sure there is a "best" state. For one thing, like CaptForce says, in some states, like FL (and CA for that matter) there is a huge difference in what it's like to live aboard in one part of the state compared to another.
Then, like a sailboat, every state will be a compromise and I would hate to pick one because I would feel like I was endorsing the bad parts
with the good.
So I would say, the best state to live aboard is the collective east coast
. Summers in New England
, winters in FL, in between seasons in between the two areas.