I'm thinking Cuba might be the perfect place to start a Liberty Territory. They are still very independent from the US, but opening up - and close enough for easy access. If we got 1000 people to move there and pay the Cuban government $100K each, we'd be matching their annual military budget of about $100M - so nothing for them to sneeze at. I'm intrigued by an island like Cayos Blancos that seems to have just two resort properties on it currently (judging by Google Earth), is on the US side and has enough empty space to get a start. There are other islands that seem to have nothing on them, but I think we're better off with whatever start we can manage to buy our way into.
Not sure if I can add links here, but I'll try: