Stocks, these folks are right -- if you're trying to redline every trail, it'd take a while. There are about 200 miles of trail officially maintained by the park authority, though there's a lot more to do if you count the unofficial routes and still more if you enjoy boating.
Roy, I haven't been up the Hathorn, but was checking it out last weekend. (Thanks Ridgerunner for the reservations!) Enclosed is a pic of the valley from Burnt Mtn (where the views from the firetower are now being overgrown even after you climb the ladder, and where we were buzzed by thousands of black flies and one peregrine). We also went out to McCarty field to scout and found what should be the terminus of the tote road route, though we did not explore. If you're out there soon, wild strawberries are abounding.