From Bay Bridge:

5th St. Exit (stay in far left lane)
Left onto 5th St.
Left on Townsend St.
Corner of Townsend and 4th St.

From South Bay via 280:

Exit East 6th St.
Right onto Brannan St.
Right on 4th Street
Left handside corner of 4th St. and Townsend St.

From South Bay via 80:

Last San Francisco Exit, take 4th St.
Stay in right lane and Exit onto 4th St.
Left into parking @ Townsend St.