A highly recommended park to hike this time of the year when it's cooler. Located on the hills of northeast San Jose, the 22,000-acre park has four trails to start out: The easy 1.2-mile Aquila Loop Trail, the moderate 3.5-mile Boccardo Loop Trail, the intermediate 4.5-mile Upper Calaveras Fault Trail and the challenging 8.4 miles Lower Calaveras Fault Trail. One of the trails can lead hikers to the lower Alum Rock park. Trails are very ideal for mountain-biking. We hiked the first two trails in three hours. The weather was ideal for hiking with breezy and chilly air at times. The park should be very beautiful in the spring time with green grassy hills..