FROM NORTH OF PAJARO DUNES:

Via Highway 17
US-101 S towards Los Angeles
Merge onto I-880 toward Los Gatos/Santa Cruz
I-880 becomes CA-17 S
Merge onto CA-1 S toward Watsonville/Monterey
Take the CA-129/Riverside Drive exit
Take the ramp toward Sunset State Beach
Turn Right onto Lee Road
Turn Left onto W Beach Street
Turn Right onto Shell Drive
Turn Left into security gated area

Via US 101
US-101 S towards Los Angeles
Take the CA-129 W exit toward Watsonville
CA-129 becomes Riverside Drive
Follow Riverside Drive until it ends
Turn Right onto Lee Road
Turn Left onto W Beach Street
Turn Right onto Shell Drive
Turn Left into security gated area

FROM SOUTH OF PAJARO DUNES:

Via Highway 1
CA-1 N towards Watsonville
Take the CA-129/Riverside Drive exit
Turn Left onto Riverside Drive
Turn Right onto Lee Road
Turn Left onto W Beach Street
Turn Right onto Shell Drive
Turn Left onto security gated area

Via US 101
US-101 N towards San Francisco
Take the CA-129 exit toward Watsonville
CA-129 becomes Riverside Drive
Follow Riverside Drive until it ends
Turn Right onto Lee Road
Turn Left onot W Beach Street
Turn Right onto Shell Drive
Turn Left into Security gated area

Here's a map:

Google Map of Pajaro Dunes