I haven't been there so I looked at the park on Google Maps. There seems to be enough sites to handle most RV lengths. I tried their booking website and it appears it works like Texas State Parks in which you reserve a spot but not a site. However you can reserve a spot according to length; 30', 40' 50'. The campground that backs onto Lee's Creek looks promising with quite a few sites that seem long enough; Campsites #50-60s and on the other side of the park sites 8-20. Can't tell how level they are. Good luck.
2008 Classic 25fb "Silver Mistress"
2015 Ram 2500 6.7L Cummins. Crew Cab, 4x4, Silver
2010 Tundra 5.7L, Double Cab, 2wd, White