Behind the lake there is a easy to miss fun and fast downhill trail that empties out onto someones property and then Alpine road. Head up Alpine and do Windy Hill for some real cardio. Numerous trails offering good uphill workouts, fire roads, rolling single track, and some jumps. I like the area for its workout and skills training, rather then its hardcore mtn biking or scenic potential. I have found a few laps ranging from 3.00-4.75 miles that get me outdoors and keep my skills up.
Trails are all great, except in the rainy season.
Horses will leave their shoe tracks everywhere and make riding the trails a bear. Climbs are relatively painless and there are some great scenery of the peninsula and the beautiful mansion houses around the the park. This is a wonderful place for afterwork biking and for begginers and intermediates. The folks that hike and ride horses are pretty friendly for the most part. Havent really seen any rangers roaming around too often either.