Have done the same thing that you are, in the past. The drive is nice, and parking was NOT a problem. Stayed at the Southern Most Hotel, nice place. Rented scooters, just to say that we had " been there, done that"
Got kicked out of Key West because of a hurricane, was nice to have our own car then, just drove back up to South Beach for a couple of days, then back to Key West. No damage, the hurricane turn after it hit Cuba.