Are you towing a vehicle?
If so then I recommend Bahia Honda state park but your time of year will dictate whether you can get a reservation in the park.
I have also stayed at what used to be called Fiesta Key KOA but the I seem to remember name has been changed and I cannot remember the name now.
For dining the Green Turtle Inn in Islamorada is exceptionally good ($$$). The whale harbor inn has a good seafood buffet. It seems pricey at $32.00 per person but the food was excellent.
More as I remember but please let me know if you have a route in mind and whether you plan to go northern route, southern route and freeway or back road.
WE really enjoyed the back roads of Arizona, New Mexico and Texas
Traveling with my best friend my wife!