For what its worth, Ive stayed at mortimer before and it was nice. Did not fill up last October untill late saturday. As well there is a nice parking area at the front with two larger walk in sites and a large covered picnic shelter that could be nice for group meals/activities. Working bathrooms and showers (2ea) and a good base camp to explore from.
As well there are roadside campsites along Craig Creek rd. No facilities, but there are two sites 50yrds apart that would fit 10 trucks b/w the two of them as long as we dont have any midnight lumberjacks among the group

this is just a 10 min drive from Wilson ck visitors center and trading post for necessities as well as pristine swimming/fishing holes for all to enjoy.
there is a FSR that leads out of murphy place road, just past the southern end of wilson creek along Brown Mtn beach road. It is NOT worth exploring. It is simply a long gravel road that is very well maintained for being an Unmaintained road. It comes out in Maple grove on US 90 near mortimer.
The brown mountain OHV trails are actually labeled FR299 at the northern end and spit out at craigs creek road (gated though) This road continues across and climbs and climbs to a nice ridgeline with a limited # of roadside campsites.
There is also the Wilson creek lodge that I have not witnessed or stayed at but the internet makes it sound promising. As well on US 90 just east of mortimer there is a small lodge that looks like personal property but is labeled a lodge at the drive entrance. It looked nice if it was open/available.
If you keep heading up 90 past mortimer camp (not town of mortimer) you reach edgemont. Proceeding into edgemont and through I am not certain what awaits you, but looked interesting. Worth the drive to see Coffey's General store there. Might even be a good place to ask for options.
HOWEVER if you turn left here up Timber ridge rd you will be heading to roseborough road. Off the side of this road is FR 192 which is not difficult but finally is something a bit less maintained than graded gravel. As well this intersection is at a long time favorite primitive camp spot with plenty of room for vehicles but it fills up early. Excellent fishing and hiking along Lost Cove trail here. IT loops back into roseborough rd via the map but I did not witness the first entrance unless it was the gated rocky creek branch access we saw.

if no loop it connects to a paved portion of 192 in BFE.
Further up Roseboro rd there is a fun but very short lil 4x4 loop just shy of rattlesnake cliffs sub'd.
another ten minutes and your on the parkway