Doctors Park offers some fantastic downhill on the Gunnison Spur of the Colorado Trail. This trail can be ridden as a loop or you can use a shuttle if riding up eight miles of road doesn't appeal to you. Most people park at the bottom (North Bank Campground) and ride or shuttle up Spring Creek Road to Doctor Gulch (trail 554). After going about eight and a half miles up the road, where the canyon starts opening up into a wide valley, look to the right (southeast) and you will see doubletrack crossing thru Spring Creek and going up the gully. At the time of this writing there was a trail sign on the south side of the creek for 554. After leaving Spring Creek Road, at exactly one mile there is a right hand turn; trail 554 continues to the right. Go right and continue up, winding your way on the doubletrack to the top of the ridge. After about three miles you will come to heavy forest. This section of the trail can be a miserable root-infested mud pit after it rains so be prepared to grind and grunt your way thru slop if there has been rain. The misery is compounded if cows or horses have recently used the trail. Continue working your way along and after another mile you will break into a large open meadow; this is Doctors Park, and this is where the real singletrack and the fun begins. From here you have five miles of fast downhill. The top section is a bit steep and rocky, but it is a lot of fun. After a mile or so you get into some fantastic cruising thru aspen forest; this is the best part of the trail and probably some of the sweetest singletrack you will ever find. Fast, flowy, and full of variety. It rocks! Let your bike run and enjoy the miles. About a half mile from the bottom the trail gets steep and rocky with fun switchbacks on a steep sideslope. If you are tired, stop and take a break so that you are ready to work your way down the steeps. The trail can be a bit technical and the drop-offs are severe, so the penalty for mistakes is high.
Now, about alternate routes, the top of the ridge is crisscrossed with a few trails, and you really can't go wrong exploring as long as you remember that you want to work your way to the southwest corner. Just remember that most of the other trails allow motorized access so they are going to be more chewed up.
If you want to have an epic ride combine this ride with the Flag, Bear and Deadman trails (see review for "Reno / Flag / Bear / Deadman"). Instead of crossing Spring Creek to go up Doctor Gulch continue riding up Spring Creek Road past Spring Creek Reservoir until you get to the bottom of the Flag trail. Go a short distance up Flag and turn left on the Bear trail. Follow Bear to Deadman Trail where you take a left and follow it back down to Spring Creek Road. From there it is a .7 mile ride back up to Doctor Gulch where you can resume the ride described above. This makes a figure eight loop that tallies up to 34 miles of riding with almost 4,000' of vertical. Yeah, that qualifies as an epic day.
If you are into camping there are many formal and informal places to camp near Spring Creek, or the whole Taylor River Valley, for that matter. I highly suggest getting the Latitude 40 map for Crested Butte.