There is a nice Air Force museum in Fort Walton Shalimar area thats worth checking out too.
We stayed at Topsail last summer for a week and enjoyed it. I was stationed at Eglin for 7 years so know the area well.
Destin is a traffic mess all the time due to being a tourist destination.
You have to plan accordingly to get somewhere because of that. It is beautiful on the Boardwalk area in Destin and nice to walk down in the evening. Plenty of restaurants and things to see and do. All the fishing boats come in and you can see them clean all the fish they catch.