Take 880 to Industrial Parkway West and head East, (who said 'head'?) or take 580 to Mission Blvd.  Drive south past Cal State East Bay and turn left onto Garin Avenue, follow to a dead end at Garin Park.  There is a kiosk there and you may need to pay $5 but let's all hope it's gender unspecified un-occupied.

Could be raining!  Could be sunny!  Could be cloudy, but regardless,  it will be muddy.  Dress accordingly.   Eagle:  5.5 miles, Turkey:  4 miles and Walkers:  2-3 miles.  Dog friendly.  Strollers?  Meh!  (not so great).   Use the lot directly ahead of the circle but the lower lot is also available.  You CAN do this !!!