Heaven help you if there is an accident. Plus, the first time we went to the Keys, we got held up at a bridge north of Key Largo for about two hours.
Plus, I find this a particularly "hard" drive because of the traffic and all that great scenery. I am always compkletely wornout by the time we get wherever we're going.
Then, when we got to Key West, the first place wanted $95 (back in the early 1990s). The next two places wanted $105 and $120. All of a sudden, the $95 was looking good. But, the room was sold by the time we got back.
Generally, the motels right when you get to Key West or a bit cheaper.
Sorry, can't help you with camping.