I'm so confused on Brown Mountain and what it actually is. I was in the area with a buddy and we both drove to check it out - Pulled in to the parking lot area right off the road and read the info sign and it seemed like there was only one trail (gravel road) that was accessible to vehicles. All other trails were for bikes, ATVS, etc. So we ended up not paying the fee to do it and turned around and went off to do something else. Of course I had seen videos of full sized vehicles rolling through but it's always just that same spot with that little mud pit.
Anyway, so yes there is Brown Mountain (maybe?). There is also a trail called Ivestor (not Investor) Gap in Pisgah National Forest. It is right at Black Balsam Knob. Go like you're going to the Sam Knob Trailhead but instead of parking in the parking lot just keep driving on past and you'll be on Ivestor Gap Trail which from what I understand is only open during the late fall to late winter/early spring. I've never done it. Might be some info out there on the interwebs but it's something I want to check out.