I camped there three years ago and used just a elbow connection that ran through a flange that sealed on the dump tube in the ground. Just like any other campground that I have been at KOA and so forth.
Sorry to be a humbug on that campground but in my humble opinion it was one of the worst one that I have stayed at in a long time. Maybe because we just left the park in Charleston SC called; James Island County park which was a great park.
2016 34RL CC; 2008 Ram Mega Cab 2500HD, 6.7L, 68RFE 6 speed, 4X4, Smarty S67