From the Boreas Pass winter trailhead, go south past the gate and look for a singletrack on the west side of the road. The trail has been recently (2014) realigned and features numerous flowy switchbacks through a beautiful aspen grove.
The trail terminates at a gravel driveway on the lower section of Boreas Pass Road (paved). Take a right on the driveway back to Boreas Pass Road and climb back to the trailhead. Utilize Illinois Gulch Road to short-cut the climb back to the trailhead.