From Gunnison, drive north on CO135 to Almont. Turn right (east) onto CR742 for Taylor Park Reservoir. The road winds up canyon for what seems like a long time (about 20 miles) to the reservoir. Along the way, it passes several Forest Service campgrounds, none of which are very large. In order from Almont, these are: Taylor Canyon, One Mile, North Bank and Rosy Lane - all within a couple miles of each other, followed by Lodgepole, Cold Spring, Lottis Creek and Lake View on the south side of the reservoir.
At the SE end of the reservoir where there's a couple stores and a number of cabins, veer right onto FR765 for Tincup. The road changes from paved to good quality gravel all the way into Tincup. In the middle of town, turn left (east) onto FR 267. The road becomes rockier and dusty from traffic, but when we last visited, most passenger cars could make it to the Mirror Lake area. At 3 miles from Tincup, there's a turnout on the left (north) side of the road. A short road loops through this turnout and there's a toilet there. This is the trailhead parking.
An alternate route that may prove a little shorter if coming from Monarch Pass toward Gunnison: Turn north from US50 at the little town of Parlin which is about 11miles east of Gunnison onto CR76. Follow this paved road NE to the little village of Ohio and continue on to Pitkin. The road turns to graded gravel here and remains in that condition as it continues north past the Quartz Creek CG and switchbacks to climb to the top of Cumberland Pass. On the north side of the pass, the road drops down on a series of switchbacks to the valley bottom and continues into Tincup. Once in Tincup, follow the directions above.
The closest camping to the trailhead is the small campground at Mirror Lake. The campground is about a half mile past the trailhead, continuing to Mirror Lake or 3.5 miles from Tincup. The last few yards up the road are steeper and rougher. There are ten sites here that cost $12 per day and there is one vault toilet and no water supply. The lake is within a short walk (under 5 minutes) of the campsites. This is a very popular area, especially on summer weekends, so don't plan on the first-come-first-served campsites being available. But, we would add that the year we visited here was over the 4th of July weekend and were very surprised to find two site open. We grabbed one and enjoyed a splendid evening. The only drawback was the myriad mosquitoes one may typically encounter this time of year around a large body of water.
For other national Forest campgrounds, see the list above in the driving directions. There is all kinds of at-large camping north of Taylor Park Reservoir.