From Silverton, drive south on US 550 to Molas Pass. The turn-off to Andrews Lake is 0.9 mile past the pass on your left.
From Durango, drive north on US 550 to Coal Bank Pass. The turn-off to Andrews Lake is 6.3 miles past the pass on your right.
Once you turn off US 550, head up the paved road. After a short bit, the road splits and to your left is the wilderness overnight parking, and to your left is the day-use parking lot at the lake. There are toilets at the day use area, as well as a paved trail going around the lake and fishing docks. This place gets a fair amount of use in the summer. It is sometimes accessible in the winter. It is less than a mile off of the highway.
There is no camping at the trailhead, but nearby at Little Molas Lake
there is at-large car-camping available on the National Forest land. I have run across one person sleeping in their car in the wilderness parking lot.