Start at the Cathrines Pass Trail from the Summer Road at Alta. Climb Cathrines all the way to the pass. Turn right on the Ridge Trail and climb (hike a bike) to a saddle where you are now staring down into Dry Fork. Sunset Peak is on your left. Hold on tight and descend the loose and rocky section of 157. Continue on Ridge 157 all the way to the junction with Tibble Fork Trail 041. (START OF TIMED SECTION) Blast down this awesome section hauling over rocks and logs. Look for the junction with mud springs (173), Stay right on the Mud springs trail. Mud springs eventually hooks up with Mill Canyon (040). Continue down Mill Canyon to the trail head.
After Party at Tibble Fork Res where you hopefully have a shuttle waiting.