Directions to the Mouth of Schoolhouse Creek
By car, park at the small turnout between University and Gilman on West Frontage Road. Parking there is very limited, so you may be better off to park at Sea Breeze Market (598 University) just west of the freeway (map and directions), and walk north on the Bay Trail paralleling the West Frontage Road to the parking turnout (walking directions).
At the parking turnout, you will see Virginia Extension service road running west and another service road running north (see image at left). Take the service road north. It almost immediately turns left, west. Follow it west until this service road reaches the bay and turns north again. The small beach at the mouth of Schoolhouse Creek will be to your left (south).
By bus: Some AC Transit 51B buses stop on University at Sea Breeze. Others end at Third Street on the east side of the I-880/580 freeway. From these, walk one block south and west on Addison, past the south end of the Aquatic Park lagoon, to cross the freeway on the pedestrian/bicycle bridge. This brings you down at the south end of the Sea Breeze parking lot. From there, follow the Bay Trail north as above.
By bicycle or on foot: The area is easily reached via the pedestrian-bicycle bridge from Aquatic Park (see above under "By bus") or the Bay Trail.
OpenStreetMap has an online map of the trails in this area.