The easiest way to explore Bear Creek is to begin at the Upper Bear Creek Trailhead. From there you'll walk 3 miles to Smith Saddle where you can take a 1.2 mile side trail to the summit of Smith Mountain. From Smith Saddle you'll drop down into Bear Creek and follow the stream until it meets West Fork Road and the San Gabriel River. A car shuttle is required unless you want to hike back the same way you came. A Wilderness permit (free) is required.
Directions from Azusa, CA: Take the Azusa Avenue off-ramp from Interstate 210 East. Follow Azusa Avenue north several miles until it becomes Highway 39. Follow Highway 39 east approximately 30 miles to the Upper Bear Creek Trailhead.