Here's another vote for going clockwise and knocking the hardest hill out early in the hike. You need a permit which you can purchase online from EBMUD for $3. Beautiful views of the hills with lots of birds and lizards. I didn't see anyone else on the trail, although I did go mid-day on a hot Thursday. Big chunks of the trail don't have much shade so bring sunscreen, and plenty of water, especially if you go in the summer.