Lots of things to do in Key West. I have been there many times. I great party place.
If you like history go the "Little White House" for the tour of President Trumans home. www.trumanlittlewhitehouse.com
very interesting! Hemmingway house; www.hemmingwayhome.com
is good too and the Audubon bird home it is at www.audubonhouse.com
There is a book on the shelves or you library called. "Florida Keys and Key West" I have read it every time we go there. Let me know what you are interested in, I'll look it up for you.
Some of the things are free &some cost a few bucks.
I relly enjoyed the Mel Fisher maritime heritage www.melfisher.org
he found wreck of the Nuestra Senora di Atocha which was ladenwith gold and silver worth millions.