I could be wrong, but I think the Dry Tortugas are called "Dry" because there is no water on them. Any water must be brought in from outside and that includes tourists. If you go there, bring lots of potable water.
There was some kind of fever outbreak (typhoid? scarlet? yellow?) when Dr. Mudd was held prisoner there, and he helped tend to the sick and did so quite well. This service got his sentence reduced, and he was out in about five years.
Mudd also did not know what Booth had done when he set his broken ankle although he was a Confederate sympathizer. His conviction was basically because he had had contact with Booth post-assassination and the Federal governemnt was hellbent on revenge.
The late newcaster Roger Mudd of CBS was a decendant of the good doctor.
Back to the subject--when something is referred to as being 'very Key West' it is virtually impossible to describe and equally impossible not to recognize after being there for a few days. It just 'is'.
Unless you have a good reason to go to Lauderdale, I'd bag that part of your Florida trip. If it is 65 in Key West then it is 50 on the mainland. Key West is always a lot warmer. It also might rain only 5-10 days a year. Good weather is almost guaranteed.
"If my life weren't funny, it would just be true. And that would be unacceptable."
--Carrie Fisher