Starting from the Grand Traverse
trail, pass Vail's helpful sign warning you of impending doom (no lift service, etc).
Fantastic singletrack slowly winds down the ridge, mostly through meadow and dying pine forest. It's a smooth, easy, gentle ride up and down for quite a ways to the end of the ridge, where there's a 100 yard spur path down to a rocky outcropping. Fantastic views abound. You can see the "Lionshead" rock formation if you look down and to the right.
Up to this point the trail is blue, or even green, and not very steep, so you could turn around and head back the way you came.
To continue down from here, follow the trails as it rapidly descends through a host of new switchbacks built by volunteer trail crews. When you get to the Lionshead rock formation, hop off your bike and enjoy the scenery.
Back on the trail, the grade eases up as you enjoy nice forested, wide singletrack to the Game Creek trail junction. Cross the stream, and follow that trail to the end.