This trail starts near the end of Peach Creek Road in one of the steep switchbacks. Keep an eye out for the trail as you climb and round the bends. You'll begin with some steep climbing up various switchbacks until you hit the junction with the Gardner Creek Trail.
From here, the grade mellows a little before a you come to more switchbacks and then you'll essentially be on the ridgeline as you climb up to Custer Lookout. Just below Custer Lookout, you'll want to keep right as you join the Custer Cutoff trail. Then as you dip below the Lookout, you'll want to keep right again.
Now you'll follow the ridgeline for a while and will continue descending steeply as you work your way down the ridge. The trail is very exposed for a while so make sure to take your time and keep in control. You'll pass two more turns, but just maintain the ridgeline and you'll continue to descend. The trees will get thicker and you'll come to a nice lake basin with Milk Lake; this is a great stopping spot for lunch. As you leave the lake you'll descend steeply down into Cinnabar Creek for the final descent down to the road.
The trail can be combined with a lot of other trails to make some interesting loops and is worth exploring. There is some great camping down in the Custer area to make a base camp for a couple of days.