Once on CR20 (on the Gunnison National Forest map this is labelled as BLM3303), drive 5.2 miles to the turnoff for Nellie Creek which is signed and turns off to the north (FR877). Coordinates are: N 38° 01' 13.88" W 107° 24' 02.68". Standard clearance passenger vehicles should not attempt to go up this road. A short distance up the Nellie Creek road is some camping, (several possible sites) but camping is not permitted along CR20 in this section of the road. To proceed further up the Nellie Creek road, a minimum stock 4WD is best to have. The road starts out kind of rough and with potholes as it passes the initial campsites and then improves in a relative sense. While rocky in stretches, there are never any difficult places up to the creek crossing. Along this stretch there are a couple other campsites right off the side of the road. In 2.0 miles, the road crosses from the east to the west side of Nellie Creek, then climbs a steep switchback and continues generally north. In another .4 mile, it makes a hard left while another road veers off to the right. This older road gives access to Crystal Peak. In another mile, the road to the trailhead begins to level out in an open meadow. From the meadow it's another .8 mile to the trailhead from there for overall mileage of about 4 from CR20. Plan on this drive taking a minimum half hour or longer depending on how much you want to rattle your vehicle.
The parking area and vicinity at the trailhead offers some primitive campsites but the ground here is not very level, so the best campsites are about a quarter mile back in the trees where there are several good sites. There's also good opportunities back in the long, wide open meadow. On summer weekends, expect the trailhead to be crowded and camp sites more difficult to find. Since Uncompahgre Peak is the 6th highest 14er, it attracts a lot of attention.