While you're looking, also scope out Henderson Beach SP which is in the middle of Destin. Once in the park you'll never know that it is downtown Destin. Not as big as Topsail but has nice private spots. It has a nice beach. It's only drawback is that it is electric, water hook-ups with a dump station. I have heard (on the rumor mill) that they are putting in sewers this year but with the economy the way it is, I wouldn't count on it. Loop C is the 50 amp loop.
Travel well, travel safe,
2006 Tiffin Phaeton - 2011 Cadillac SRX