This is an excellent up-and-back segment of the CT that will give the intermediate rider a taste of alpine riding without the deep commitment of some of the area loops.
Park at the Molas Pass overlook and carefully cross the highway to the trailhead a couple of hundred feet downhill. Alternately, you can use the parking area near Little Molas Lake.
While the grades are forgiving, this is a serious trail. Take plenty of liquid and calories, and be prepared for wind, rain, sleet, and hail.
Head west, passing Little Molas Lake and gradually climbing into a clear area that is an old burn. The first three miles are all uphill so you can turn around at any point and be pretty confident of getting home. The trail is a bit rutted but in good condition. Watch for hikers and others.
Beyond 5 miles the trail enters forest, becoming narrower with a steep cross slope in places. There are few technical obstacles but some riders might want to walk short sections that are above cliff bands.
On the way back there are some hills, but they are relatively minor.
As you get out about 9 miles there is some muskeg (swampy) trail but it is not too bad. Keep an eye out for the interesting "karst" or cavernous terrain: a spring, sinkholes, and a stream that sinks underground.
At the junction with Engineer Mountain Trail
continue on to a big loop or roll back east.
Note that the segment of the CT immediately to the east passes through wilderness. The next section that mountain bikers can ride is Colorado Trail: Stony Pass to West Pole Creek Trail