I ran this loop yesterday as well, I won't be able to post my track from my watch until I get acces to a computer tomorrow night, but I came in at 7 hrs 21 min. Surprised I didn't see Giff yesterday on the route, what a coincidence we were doing it the same day! I started at the Knowles trailhead, this time is subtracting the 2 miles it takes to get up to the start of the loop.
Here is the track from my GPS watch (this was my first time tracking myself with a watch on a route like this and I didn't know the battery would die so quickly) It has my whole route up until the last 3 or so miles. www.movescount.com/moves/move107825668