From the center of Gunnison, drive west on US50 for appx. 15.1 miles and turn north (right) onto FR724 (also known as the Rainbow Lake Road or County Road 3037). The dirt road is not well marked. There's just a small sign so it's easy to go breezing by.
If coming from Montrose, after US50 crosses Blue Mesa Reservoir on the bridge, continue driving east another 7.1 miles and turn north (left) onto FR724 as above. Again, the road is poorly marked.
From the turnoff for FR724, it's appx. 11 miles of graded, dirt road driving to the trailhead. The road begins by passing through the open sagebrush foothills north of the reservoir and climbs steadily, but not too steeply. We were a little surprised to find the road fairly narrow and nearly a one-lane path at times, even though the maps indicated it should be better quality. It was not rocky however or too rough, just terribly wash-boarded. On our drive in we spotted a bear briefly and a deer along the road farther up in the aspen forest. The 11 mile drive required about a half hour. The actual trailhead is about a quarter mile past the turnoff for Rainbow Lake. Also, there is a much smaller pond on the right shortly before reaching Rainbow Lake. Do not confuse it with the larger Rainbow Lake. The trailhead parking area is sizable and can accommodate probably a couple dozen vehicles. One could easily car-camp here overnight, but there's good camping back at Rainbow Lake and the smaller pond.
Several at-large, primitive sites can be found on the drive in to Rainbow Lake, mostly along the last few miles, once you get up into higher altitude forest. The best camping will be at the small pond located on the east side of the road, shortly before reaching the turnoff for Rainbow Lake, and at Rainbow Lake itself. There is no official Forest Service CG, hence no facilities.