Pacific Coast Highway Ride Leg 1: from Fort Bragg to Eureka via the Lost Coast.
From Eureka take US101S to the junction with CA211 (Ferndale exit). Take CA211S at the CA211/Ferndale exit. Go through Ferndale, turn right near the end of the main street and then left onto Mattole Road. Proceed on CA211 (Mattole Road) through Petrolia and Honeydew until it joins CA254 above Weott (the junction of Mattole Road and CA254 is tricky; see map and description below). Stay on CA254 (Avenue of the Giants) to the end of it at Phillipsville; then get back on US101S. Continue on US101S to the junction with CA1 at Leggett, CA; take CA1S to Fort Bragg.
Detailed map of the Mattole Road to CA254 junction above Weott:

As you come out of the redwoods on Mattole Road, go underneath the freeway
and turn RIGHT onto the bridge. Go across the bridge and continue
STRAIGHT on; that is CA254 SOUTH and the Avenue of the Giants. After
you pass through Phillipsville, the Avenue of the Giants runs back onto
US101; the distance from the right turn onto the bridge until the end of
the Avenue of the Giants is about 19 miles.