This is turning into a football game...hoping neighbors will be selling parking next door...
These are some local options for lodging unless you are deadset on camping. Carville, TN is 10 miles south of RRB at exit 134 vs. 144. From exit 134 of your can cross over the interstate stay on little black top road it's old hwy 63 legal ATV route, up the road is a bridge off to the left with RR tracks just past the bridge. At that spot is a large gravel opening that is a legal trailhead parking area for Royal Blue, you can part trailer and unload there.
Now to get to RRB campgrounds you take SXS back onto little black top road going North (left turn) stay on it until you come to a T that is new Hwy 63 there is an ATV route sign there pointing right, turn right onto Hwy 63 and take the first road left (Stinking Creek Road) also ATV route sign pointing left. Once on Stinking Creek Road stay on it over I75 and RRB Campgrounds is 4 miles down on the right. Should be able to get there in about 20 minutes at 30 mph from the parking area.
Also you can camp at the parking area should you want to.