From I-70, west of Idaho Springs, take exit 238 for the Fall River Road/CR 275. This paved county road 275 ends in the vicinity of a mountain village called "Alice," mostly a collection of summer cabins, etc. This is the same road that leads up to the well-known St. Mary's Lake and Glacier. The road follows the Fall River in a generally NW direction. After 6.6 miles, the road makes a second, abrupt switchback to leave the Fall River drainage and climb up to St. Mary's Lake and Alice. Continue north into Alice. Watch for a couple of parking lots on the left side of the road, one larger lot before the trail up to the glacier, and the other just after the trail/old roadbed heads up to St. Mary's Lake and Glacier. Coordinates above are for the larger parking lot. The smaller lot is directly west from Quivira Lake. If you come to the end of the pavement and Silver Lake, you've gone past the trailhead and parking lots. These two lots now require a $5.00 fee to use. There is a self-serve ticket station at each lot.
This entire area of Alice is private property. For at-large, primitive camping, you're better off driving back on one of the Forest Service roads such as FS 701.1 up to Fall River Reservoir. If you don't mind packing in some gear, you could head up to St. Mary's Lake and set up a tent if camping is allowed there any longer. Check with the Forest Service.