There are three trailheads, one each at Laguna Mountain, Sweetwater, and Short Fence. From the Laguna trailhead, a somewhat rugged hike will bring you up and over a ridgeline and then drop you into Miller Creek canyon, which is pretty easy going. If you follow the creek, you eventually will find a series of waterfalls up in the gorge.
From Hollister take State Highway 25 south. Turn left onto Coalinga Road and look for the access points located on the west side of the road.
http://www.tripleblaze.com/trail.php?c=3&i=8034