This is a popular motorcycle and ATV trail that follows a ridge with tough climbs but awesome views of the surrounding country.
Get onto the West Mountain Trail from No Business Saddle. Almost immediately, the jeep trail climbs up over 1000 feet on switchbacks to the edge of the ridge. Nice start! It'll level out a bit over a few miles and then climbs again at a good grade for the next five miles toward Lone Tree Mountain. The final approach to the backside is a hike-a-bike spot unless you want to go all out and burn all your energy here...the rest of the ride will suck if you go nuts. Nice downhill after the peak for about three miles and then at the edge of the rim you'll see a junction with the Arling Trail. This is narrow and full of bushes but cool single track. You can bail out here if you like, The West Mountain Trail continues, though. The bail-out will take you to the West Mountain Road again. If not (go for it!), descend along the ridge with some short hills until about five miles past the Arling Trail. You'll see a four-way junction here. Go left onto USFS 435 and head downhill toward the West Mountain Road, the Cascade Reservoir, and Cascade. Go grab some beef jerky at the Texaco!
How to get there:
From Donnelly, turn west at the Stinker station and follow signs along the road to Rainbow Point campground. Cross the Cascade Reservoir, and turn right on USFS 186 towards No Business Saddle. At the saddle, pull over at the junction with West Mountain Trail on the left. Shuttle: leave a vehicle a the junction of West Mountain road and USFS 435 on the west side of Cascade Reservoir, or at the other bail-out point along West Mountain Road.
DO NOT attempt this unless you are used to 25 plus miles of tough terrain in one day.