Been to the Keys many times. TBH, Key West is basically a tourist trap. But if you go, try avoiding hotels. Island City House was a great B&B to stay at, and pretty close to the action.
But best trips we had staying in KW we rented a condo in Truman Annex. Condo came with two bikes, had a full kitchen, outdoor grill, everything you needed. We literally parked the car for a week and moved it once. We’d ride to Fausto’s Market every morning, pick up fresh seafood, veggies, and killer Cuban bread, instead of hitting tourist trap restaurants for most of our meals. Did have killer meals over the years at Blue Heaven, El Siboney, and Pepe’s. There’s little convenience store next to the Courthouse that used to make killer Cuban sandwiches. Hogfish Grill has always been good for us. BO’s Fishwagon And Garbo Grill were spotty, very good at times, less than average other times. Most restaurants in KW tended to be overrated in our opinion, which is why we tended to just cook fresh stuff ourselves.
Last couple times down we’ve stayed at a townhouse on Marathon, right on the water. Great views, great central location to do a lot if you plan on flying in and renting a car. If you do that, go to Robbies on Islamorada, feed the tarpon. You can drive to Bahia Honda Park. You can do a 4 hour headboat trip for about $40 apiece, let them clean your fish and have a great meal. Couple really great restaurants around Marathon, ranging from fairly expensive to a hole in the wall Cuban place where no one speaks English.