There's basically nothing but Planet of the Apes (very broken pavement and dirt) and hwy 1 between Pacifica and Half Moon Bay.
If you want to go in that direction, and be on the ocean side, I'd suggest starting further south. Pescadero would be a good spot; you could ride north on Stage Rd, up hwy 84, right on Pescadero Creek Rd, stay right on Pescadero Creek Rd, then get back to Pescadero again and have garlic artichoke bread.
In that area you also have west Old La Honda and west Alpine which could be incorporated into this loop.