From Sunset or South Bay via 280: Take 280 North to SF. Exit onto 19th Avenue/Junipero Serra (Cal route 1 north). Take 19th Ave. about 4 miles to the EDGE of the park, but DON'T go in. (If you do, see the directions from the north.) Turn right onto Lincoln Way. Go east 10 blocks (about 2/3 mile) to 9th Ave. Turn left and enter the park. Follow Martin Luther King Jr. Drive around the Arboretum (about 2/3 mile). Just past the edge of the Arboretum you'll see Strawberry Hill on your right, with a one-way exit and a one-way entrance. Take the one-way entrance, and drive around the hill to the parking lot. If you reach the busy intersection at Cross-Over Drive, you missed the turn; go FORWARD, turn around, and try again.
From Richmond or North Bay via GG Bridge: Stay to the RIGHT after the toll plaza and exit onto Cal route 1 south (MacArthur Tunnel, Park Presidio Blvd., 19th Ave.) About a mile past the tunnel, BEFORE you get to the park, turn right onto Balboa or Cabrillo. (If you miss it and enter the park, see the directions from the south.) Then turn left onto 14th or 15th Ave., then left again in a block or two onto Fulton. Go east 4 or 5 blocks (about 1/4 mile) to 10th Ave. Turn right and enter the park. Turn right again onto JFK Drive, and watch for the Stow Lake sign on your left in about a mile. Turn left and drive up the hill. If you reach the tunnel/overpass at Transverse Dr., you missed it.
From elsewhere in SF, East Bay via 80, or South Bay via 101: From the East Bay, take the Bay Bridge into SF, and follow signs for 101 NORTH. From the South Bay, take 101 North to SF. Follow the 101 North freeway all the way to the end, PAST the 101 exit. Exit onto Fell Street. Take Fell St. west, along the Panhandle Park, and into GG Park at Stanyan St. (about 1.6 miles). Stay to the RIGHT, and bear right onto JFK Drive as the main traffic stream curves left. Follow JFK Drive past all the sights, about 1.2 miles, and watch for the Stow Lake sign on your left. Turn left and drive up the hill. If you reach the tunnel/overpass at Transverse Drive, you missed it.
Alternate access to Stow Lake: View these videos for access from Martin Luther King drive and the Boathouse Parking area.