FOR THE CLASS 1 HIKE: With massive construction in the area, the directions to the parking area need to be revised:
At the intersection of Willow Road and Wildcat Canyon Road, take Wildcat Canyon Road 3.3 Miles to Blue Sky Ranch Road and turn LEFT to Oak Oasis Park. Drive straight ahead to the paved parking. On foot, reverse your path and hike back accross Wildcat Canyon Road and continue up the road to the trailhead (approximately 1 mile). The ranger told us that when construction is finished, there will be a tunnel under Wildcat Canyon Road to facilitate safe passage.
Warning: there is no Class 3 TrailHead or trail. You will be trespassing just to get close to the bottom of El Cajon Mountain. Friends and I tried today, April 12, 2014. Very frustrating and had to turn around mid hike. I would not attempt the above directions. Possibly come from the El Cajon Reservoir.