Teri, yes, vacationed there twice. It's a beautiful island. Not very commercial at all. The locals live the hardscrabble life of fisherman, except for the folks in real estate/tourism.
Bring your bike. There is a path that runs nearly the entire length of the island, and there isn't much auto traffic. It will be blistering hot, so make sure you have a water bottle somewhere on the bike. Kayak would be fun, but check with the locals about currents. Some parts of the Gulf are famous for hefty riptides. If you didn't have an iron trailer, I'd suggest bringing the Triton down. The bay side of the island is very calm water and the fishing opportunities are enormous. I came home from the last trip wanting to trade the Nitro for a skiff...
Bring your favorite spices for shirmp, because you can buy shrimp just off the boat and have them on the grill five minutes later. There are a just a handful of restaurants and watering holes nearby, so you should be prepared to cook if you like some variety beyond those places.
Also, if you have them, bring a good pair of binoculars. Great bird and fish watching opportunities. The place is absolutely teeming with wildlife.
If the wind is right, as you go across the long causeway to the island, the pelicans will soar right next to your car's window, not ten feet away. They look prehistoric.
Now I wanna go back there...