I've run all of Brown Mtn in a 4wd truck (except for one really steep hill.) Once you get past the legal part, it's pretty good. Don't know why they don't let Jeeps and 4wd trucks on the rest of the mountain, as they fit just fine. Now I did this over 10 years ago, and basically drove past the sign at the end of trail 1 saying no Jeeps allowed past this point and by the time I realized what I did I was in too far to bother turning around. If you go for the legal section, well that just isn't any fun and is over really quick. It's much more fun to explore the forest service roads off Wilson Creek Gorge.
If while exploring the area you come across the following situation, tell me where it is, as I can't remember. Anyway, you go down a dirt road. You get to a giant concrete paved bridge over a creek/river. If you cross the bridge it turns back to a dirt road, then quickly turns into a nice paved road with giant stone blocks along side the road, placed nicely as if put there by stonemasons. After a few miles the road turns back to dirt and ends. I call it the bridge to nowhere, and I can't remember where it is. Might be in the Boone area, might be in the Murphy area.