My lap started and ended at the Red Creek Trailhead, and my time begins and ends from there which is about 1/2 mile before the circumnavigation loop truly begins. The prior submissions have also included the Bear Rocks side trail which is not a part of the loop and added substantial time to the prior attempts. The true "Circumnavigation" loop is only about 19.5 miles.
I had a blast on this run. I am an intermediate runner and this time can certainly be beaten, and likely has been beaten several times before but not recorded. There are good periods of run-ability of this trail for the first 16 miles. Its Dolly Sods, so there will always be lots of mud to deal with and to slow you down. The last 3 miles however were an absolute slog. It was almost completely mandatory walking from miles 15-18 due to the overgrown rhododendron, very deep mud, and faint trail. I got off trail several times and logged a smooth 20 minute mile for mile 18 (for all of the above reasons). The last mile of the circumnavigation loop is quite steep, varying from -10% to -25% grade with loose footing, narrow trail, and fairly sheer drop to your right, so moving is slow there. You cross Red Creek twice and have to wade. Don't waste time trying to find a dry path, because they don't exist. Unless it's a big drought you will be wading either way so just send it right on through.
Lets see someone do this in 4 hours! I know it can be done!