Fort Pierce is located in a pretty good spot. If you don't mind a little drive you can airboat the southern extremes of the St. Johns River, Lake Okeechobee, and maybe even the northern extremes of the Everglades. The only problem with my advice is, that it's not first hand. I haven't ran down there either, but would like to someday.
I do spend a little time in Fort Pierce every now & then, but it's for snook fishing & I leave the airboat at home. If you like fishing, don't leave your fishing rods at home.