Take a walk on the wild side
Great waterways for canoeing and of course the amazing Mammoth Cave(s) nearby. If you aren't afraid of cramped dark spaces, squeezing through tight spots and darkness, try the wild cave tour. Otherwise go with the easier historic tour.
Campground itself is close to at least a dozen trails and less than a mile from the visitor center. Vault toilets and nice shady campsites.
Be careful and don't bring white-nose bat fungus to any new caves! There is a protocol to follow to prevent it. Read the literature provided at caves.