I couldn't do more than what HardDrives parents do - 3/4 moths in the winter.
I have flown there quite a bit as a Navy pilot - a few of the NAS Key West base CO's were good friends of mine. I have also known a few folks that were stationed there.
I get the vibe and the life style since I am a water guy...but (there is always a but) the Keys are a lot more remote than you think. They are the last stop on the trolley line.
Everybody I know who lived there loved it for the first year or so, but with few exceptions were ready to leave when their tour was up.
Remoteness was part of the problem - it is a few hours to get anywhere to then go somewhere
Again, I like the Keys but just not for more than an extended stay a few times. I'll come and visit!