Drop some Grand Isle Campground knowledge on us.
Grand Isle is the only inhabited barrier island in Louisiana and has about 1,300 year-round residents. During my visit in early April I basically had my own private beach. This is because the island is actually a world class fishing and birding destination; not a beach destination. The campground is frequented by fishermen and fisherwomen.
It's the Gulf- keep that in mind and you'll have a great time. Definitely bring an arsenal of mosquito spray and keep your fire going for smoke protection. Also, be aware that the shrimp boats will make noise until about 3AM. Other than those two caveats, Grand Isle is a beautiful place- especially if you like to bird watch.