This was a great hike! Neither my wife nor I had done it before, so it was particularly fun!
It is referred to as Cold Spring Trail - Middle Fork on HikeLosPadres.com.
The hike starts at the Cold Spring Trailhead at E. Mountain Drive and quickly crosses the creek to head up the West Fork of Cold Spring Trail. Take the cutoff to the right to Tangerine Falls and shortly thereafter, look for a sharp cutoff to the left (heading straight on the Tangerine Falls Trail takes you to the base of the 100' falls and taking this trail to the left takes you above the falls to views, deep pools, the remnants of an old homestead and best of all, seclusion! (We were on the trail for nearly 5 hours and didn't see a single person.) At around 1.9 miles notice a steep trail up to your right, you will come back here if you wish to finish the trail at E. Camino Cielo. To see the remains of the old homestead stay left on the main trail and follow it for another .5 miles or so to the the old root celler from the Romero homestead. Apparently there is some old farm equipment to be found, but we didn't see it. If you return to the steep trail off to the right at mile 1.9 you will have about 2 miles of steep climbing with very few switchbacks to E. Camino Cielo via a elatively new, but good trail. The trail passes over a knoll and follows a ridge up the E. Camino Cielo, so you will need to have left a second car there or get someone to pick you up.