7350 Johnson Drive

From Interstate 680, exit at Stoneridge Drive. Go east on Stoneridge to the first traffic light. Turn right (south) on Johnson Drive. Park where convenient.
or
Going East on W. Las Positas, Turn Left onto Payne Road - corner of Payne and Denker

You can park on the Johnson Drive side (off Stoneridge Drive), or you can park on Denker