January 8, 2012
HUGE trail system. I rode this area twice, 2-3 hours each time and I was in two completely separate areas. I rode only Brown Mountain and then Starr Pass -> Yetmen -> Bowmen -> Hidden Canyon (See sdmb.org for better trail info)
Brown Mountain: Starts out rolling through the desert and gets technical quick as you drop into/out of a wash. Then it's sweet, rocky singletrack with some tight switchbacks and a lot of climbing. On the way up to the top and at the top you have some great views. Then the way down is even more technical. Large drops, huge rocks, and tight, steep switchbacks. Oh, and cactus lining your decent.
Starr Pass/etc: Starts out with some techy climbs and descents. Both are very fun. Hidden Canyon has some Hike-A-Bike. The switchbacks are insanely tight/steep but it's a great trail.
Overall the park is a "More difficult" trail but it has some areas that are definitely black diamond or greater.
Sweetwater and Robles Pass