Unfortunately, your trip is still in high season. Going in May or later will open things up and knock down prices.

The Keys, with a few exceptions are highly developed.

Nobody is against saving money, but considering the circumstances, why not bite the bullitt and reserve space in some decent campgrounds or motels? Yeah, it will cost, but your payback will be a worry free enjoyable trip.

The Keys are hot, humid, and very buggy. Not a place to skimp on accommadations if you can do otherwise. Having a clean space or air conditioned room and access to showers and fresh water, not a bad thing.