You've provided some great info on the other Thread (short visit to key's) - we could have used your expertise this past New Years
Went to the Keys for New Years without advanced reservations - seemed 1/2 the Country ended there because a bitter Cold Front chased everyone South, plus many areas were still closed from the Hurricane damage - the place was booked solid.
The Locals are great !!! Amara Cay Resort in Islamorada allowed us a spot at the end of their parking lot for a night on Dec 31st (then also gave us first chance at a room in the resort for New Years because of a cancellation).
The following 2 nights we spent in Key West, and again no reservations available. Stayed first night parked In the lot of an Auto repair shop on north end of Town (while driving around we spotted a guy locking up the place and just asked if they would mind - he said no problem as long as we were on our way by 8am the next morning). Second night we parked on the back side of the IHOP parking lot...promised the lady we would be in for breakfast in the morning - she laughed and gave approval.
Been several times, and always have a blast.