We previously hiked from Bouquet Canyon alogn the Pacific Crest Trail going roughly north. Info on that hike is here. This hike starts at the same place on Bouquet Canyon road but goes roughly south on the PCT toward Agua Dulce.
Parking is at a turnout on the south side of the road. The trail is marked on both sides of the road with Pacific Crest Trail signs. However, the signs are small and easy to miss from the road. An adventure pass is needed to park at the trailhead. The Santa Clara/Mojave Rivers Ranger District (661 296-9710) is where to find info. It is listed on the Forest Service contact info page.
The trail is hard to plot because a lot of it is not marked on the topo maps. It was necessary to go to Gmaps and use the satellite photo. In the satellite photo you can clearly see the turnout we parked in and the trail on both sides of the road.
Here is the hike plot from Gmaps Pedometer. Trimble Outdoors has good information about the trail.
Here is a link to driving directions on Google Maps.