Here is what I have found on what is known as the "Iron Gap Trail"
This is a public, unkept 'road' that runs just south of Winchester, TN (Belvidere) down across the TN/AL border to Estill Fork, AL.
It runs rougly 10 miles on the TN side, and 6 miles on the AL side; for a 16 mile one-way trip.
In runs across WMA and Watershed land, but requires no permits.
The TWRA/EPA officers request however, to not 'run the creekbeds'. Crossing creeks is fine, just not running the creeks as if they are trails.
Tim, if Im not mistaken, TNRovers is running this trail in May.