I was in the area hunting Firestone, the oldest active cache in the Bay Area, and I noted the lack of caches in the area. While I was exploring, I found myself on an unmarked trail parallel to and up the hill from the Coastal Trail, the one that Firestone is on. This trail isn't on the park map or OpenStreetMap (at least at the time of publication) but it does appear on Google Maps. No bushwhacking is required and I strongly discourage trying it, don't mess up this beautiful place. I've added a waypoint to mark the junction of the unmarked trail with the main trail.
The sun was strong the day I was there (early June) and I found myself in a beautiful shady spot with an amazing view (picture below):
The hide is a 16-ounce (half-liter) camo taped peanut butter jar.