Hi Des,
I concur with above advice as previously a frequent visitor to the USA for both vacations and as a professional pilot. Health insurance is absolutely vital. Have had colleagues injured in a RTA when they were shunted from behind while stationary in a queue. Covered by BA as on duty, the bills were $ 10s of thousands for a couple of limb fractures and other injuries. Mosquito born diseases in Florida are thankfully rare but do exist. It is simply too risky. Your plans sound great fun. My travel days are over with increasing in-capacitance, annoying for my wife as I still get free tickets,
I phoned Direct line when I left the scheme in August. Very helpful and provided letter confirming no claims. New Kodiaq £400 pa with Alliance, better than expected. Good luck and have a great trip.