My in laws recommended just recently to maybe stay some where midway down the keys as a home base. They said there are so many different places along all the keys that you don't wanna miss.
I had been thinking about blue water before that, but may need to change my mind. State parks are difficult to geti not, but they also don't offer the amenities that private parks will. Also depend a on your budget. Some place like blue water will be over $100/night while others will be less and even half.
We have been talking about going down this next year, but wife mentioned last night that she would love to go back to Destin also.