There is access to the Bay Area Ridge Trail, the Chabot to Garin trail and over five miles of trails in the Five Canyons Open Space.
From I-580 eastbound from San Leandro, take the Grove Way exit in Castro Valley; right at the exit onto Grove Way; left on Center Street; left on Kelly; and left on Woodroe to the park entrance.
http://www.tripleblaze.com/trail.php?c=3&i=7042