We vote for Mrs. Macs kitchen as well and if you stop at a tourist welcome station at the top of the Keys on your way down you will often find discount coupons..including Mrs. Macs. There are also shell shops in the mid to lower Keys that have not only unique shells but great gifts as well.
As for Key West..park the car in an off main street ( Duval) parking lot and walk through the downtown area. You may be followed by a beautiful rooster looking for handouts. A trip to Key West isn't complete without quaffing a few at Sloppy Joes and they have a small souvenir shop as well. Be advised that the Sloppy Joes on Duval is NOT the original..it's around the corner on a side street. In Mallory Square there are lots of shops and don't miss the Aquarium and the Sandal factory. Once back in the car you may want to tour little Havana..an area of Key West with original Cuban style cottages/homes built by Cubans who settled in Key West in the fifties. And don't miss mile marker # 1.