I've done the route a couple of times in winter when brush is less of a problem. Round trip to either Williamson or Tyndall is about 16 miles via Shepherd Creek to Williamson Creek to Williamson Bowl. That route gives you access to several routes on the north side of Williamson as well. The lower section is brushy, but I don't remember it being as difficult as George Creek. I think Bairs Creek is by far the quickest and easiest way up Williamson, at least in winter.