Red Mountain DH Trails
Red Mountain, just north of Vernal, has two DT trails that are usually ridden separately as advanced-technical shuttled downhills. You can, however, combine the trails to ride Red Mountain as a brutal loop. Another riding option is to substitute the Rojo Trail for a portion of Red Mountain West, either uphill or downhill. For the shuttled downhill, you'll leave a car at the bottom of either DH West or DH East, then park below the top of the mountain. Yes, below. You'll push your bike 500 vertical feet in 1/2 mile to reach the top. The downhill has 1700 feet of elevation change. 
Riding notes, Killer clockwise loop for XC riders:
0.0    Ride north on DT N40 32.678 W109 35.275
0.5    Find Rojo on your left across small wash
         just as you hit the edge of the mountain
         N40 33.024 W109 35.059
3.6    Left uphill on DT N40 34.263 W109 34.013
         DT forks and rejoins multiple times
6.0    Top of mountain
6.1    Pass ST for shuttle ride, enter DH East
         N40 35.619 W109 33.189
9.0    Fork R for classic, L = harder
         N40 33.896 W109 31.958
10.0  If you kept L, go straight N40 33.294 W109 31.484
         If you went R, fork L N40 33.321 W109 31.759
         then R at bigger DT N40 33.294 W109 31.484
10.5  At highway, go south (R) N40 32.867 W109 31.554
11.5  Straogjt for roadie return N40 32.028 W109 31.337
         (R = Steinaker, find ATV track for return
         N40 31.930 W109 32.001)
13.7  R on 3300 North N40 30.256 W109 31.743
15.5  Follow road L
15.6  R on 2500 North N40 29.484 W109 33.463
16.7  R on 2500 West N40 29.505 W109 34.622
20.5  Back at car
Downhill navigation Red Mountain West DH:
0.0    First, get your bike up the steep ST from
         the upper parking area
         Turn hard right (west) on the DT
         N40 35.619 W109 33.189
1.0    Alternate paths fork and rejoin
         Up-and-down gives way to descent
1.9    Optional ST route on R
2.4    Option Rojo on your right (adds 1/2 mile)
         N40 34.263 W109 34.013
3.9    Keep R (L = connector to Steinaker)
4.4    Rojo joins DT from right N40 33.024 W109 35.059
4.9    At bottom parking N40 32.678 W109 35.275
Downhill navigation Red Mountain East DH:
0.0    First, get your bike up the steep ST from
         the upper parking area
         Keep left (eastbound) on the DT
         N40 35.619 W109 33.189
2.9    Route splits, R is classic, slightly easier
         Straight (L) optional.
2.3    Head toward highway after dropping off slickrock
4.0    If you kept L, keep straight here N40 33.294 W109 31.484
         If you went R, fork L N40 33.321 W109 31.759
         then R at bigger dirt road N40 33.294 W109 31.484
4.4   At bottom parking N40 32.867 W109 31.554

Getting there:  While driving toward Vernal on US-40, crest the hill and pass the rest area just before town. As you encounter buildings, watch for 2500 West on your left. As of 2010, it's the 3rd street, but it depends on what you count as a street. Turn left on 2500 West.
Shuttle West or parking for Killer Loop:  Keep going north for 8 miles. At N40 32.678 W109 35.275, there's a parking area on your right. The trail is the doubletrack heading north.
Shuttle to Top: Continue north on 2500 West to mile 13 from US-40. Spot dirt road on the right at N40 36.447 W109 33.865. Keep right at the fork and park at the end of the road. Start "riding" south on ST at N40 35.896 W109 33.293. The top of both trails is 0.4 miles and 500 vertical feet uphill.
Shuttle East:  Go north a couple of miles on 2500 West as above, but turn right at 2500 North. At the T intersection a mile later, turn left, then veer right. When the road intersects SR 44 two miles from 2500 West, turn left and drive 3.3 miles north. Turn left into a dirt road with an adjacent small parking spot at N40 32.867 W109 31.554. Now take your Top vehicle back to 2500 West and continue north as described above.