Just a head's up that might be pertinent to your "which campground" conversations -- my wife and I stayed the last three nights at a place in Elk Park, NC. Granted it's farther north and east than you have been looking, but I can tell you it's a perfect little spot for 6-8 campers. And the riding here is wonderful. IMO, very similar to where you are looking, but less traffic.
Very private, very secure, very gracious hosts. Just one bathroom/shower, but extremely clean. Plenty of space for tents, campfire, shelter if it rains, etc.
Here's a Facebook link to check it out, and I'm available to give details if your interested.
https://www.facebook.com/Mountain-View-Moto-Campground-615636078583390/Good luck with the event, sounds like a blast.