You probably won't have a problem getting a site. It's out a long dirt road so it doesn't get as much traffic. Along this dirt road are free camp sites, not marked but you can tell where they are. Campers will have to park by the road but there's no traffic and is all wooded.
The campground itself is kind of on a hill so riding a bike would be a work out but parking was level.
Spruce knob was defiantly worth the 20 minute drive.