Interactive map here. The trailhead is at the far eastern end of this track, on Rocky Fork road, a paved road that turns north off Hwy 352, a few miles northeast of Flag Pond, TN.
I was trying to get up to the AT, but first ended up winding around to the south, and climbing further up Flint Mountain.
On my way back, I found another old road that I did not notice when I first went by, that might head up to the AT. Will have to check that out on another trip!