Most likely you won't get satellite reception if you are in the interior of the campground. The campground is heavily covered with trees. On the outside, street side, if you have long enough coax, you can place the satellite outside the trees.
Have you looked at staying off the island and driving there for the day? Coastal GA RV Resort is about 20 minutes away from Jekyll Island, about a mile off I-95. The park is only a few years old and the trees haven't grown tall enough to be a problem yet. Reception will not be a problem. The bugs on Jekyll are really bad this time of year, especially at the campground. They won't be nearly as bad off the island.
-Michael