Not happy unless your fat-tire experience is rough-and-tumble? Then head 60 miles north of San Francisco to Annadel State Park
on the northern end of Sonoma Valley, where 40 miles of rugged-ass mountain biking trails offer abundant options. Test your legs on steady climbs, scramble your eggs on boulder-strewn downhills, and even take a dip in a little lake. We recommend zig-zagging for 10 miles through woodlands, meadows, marshes, and chaparrel-covered hills on a collection of trails that starts with Spring Creek Canyon. Deep in the park is beautiful Buick Meadow (pictured). Back here you can’t hear anything other than the occasional whirl of a passing mountain biker. Marsh and South Burma trails offer some rolling, tight singletrack, while Rough Go Trail lives up to its name. Hold on tight for this final downhill that isn’t for everyone: ostrich egg-size rocks cover the trail, making for a jackhammer descent. Rock on.
Park at the Newanga entrance to Spring Lake Regional Park ($6 entry fee from fall to spring; $7 in the summer) by the horse trailer parking (directions can be found on their Web site). Go up the dirt fire road past the yellow gate. This is unmarked Spring Creek Trail. After 1 mile, you’ll reach a fork with an info sign. Go right on Canyon Trail. In another 1.5 miles, you’ll reach Marsh Trail. Turn right and keep climbing up Marsh Trail. In 2 miles you’ll reach South Burma Trail and turn left. Follow South Burma Trail for 2 miles to the Warren Richardson Trail (a fire road). Turn right and go just .2-mile before turning left on North Burma Trail. Follow this for 1 mile. Turn left on the Oak Trail and follow it 1 mile to Rough Go Trail. Descend Rough Go Trail for 1.5 miles back to the Spring Creek Trail.