Take I-70 to the Bakerville exit (#221). Leave the highway and drive south over to the dirt parking area near the start of Forest Road 189. This is the winter trailhead and, even if the upper road is open, low-clearance passenger cars should park here. It's almost 3 miles to the summer trailhead. Reach a junction after one mile - stay straight and follow the sign for the Grays Peak trailhead. Continue another 2 miles to the trailhead at 11,280'. There are restrooms and a few dispersed camping spots near the parking area.
The road to the trailhead is somewhat rough, so a good clearance vehicle is recommended. If you miss the new trail (to Torreys) at 13,200', you can also turn right off of the corner of the large switchback (at 13,800') on the Grays trail.