Sounds like you're talking about the Lost Coast ride, like. Dude. You want the exit off 101 just north of Fortuna marked "Ferndale" (either from the north or south). When you get into town, take the main street through town (you'll be on Ocean Ave.) till you come to a handmade-looking sign, yellow letters on brown, reading "Capetown - Petrolia" with an arrow pointing left. You can find it on Google Earth (street view) if you zoom in on Ferndale and look for where "Mattole Road" comes into town. That's your road. You might think you're going up somebody's driveway for a while if not for the sign. It climbs and climbs, usually into fog, from my experience, but it will give you great views, twisty roads, quite a few bumps and some gravel spots, till you're riding along the coast. Emptiest coast road you'll ever find.
After you ride along the coast for a while you'll head back inland. Mattole Road just winds everywhere, pretty much all points of the compass. You'll finally reach Honeydew. From there, I suggest over the bridge and follow the road that takes you back to Humboldt Redwoods State Park and the Avenue of the Giants (scenic frontage road that parallels 101). Very interesting in there, too. You'll gain a lot of altitude on this ride and lose it all again. I suppose it could be 90 minutes or so from Ferndale to the state park.
There's another option at Honeydew, but it's very rough, from what I'm told, largely unpaved, that leads to Shelter Cove. You could also get there by a better road quite a few miles south of Fortuna off 101. The exit is marked Shelter Cove. But IMO, you'd enjoy the Lost Coast ride better.
Lots of us know this road. Maybe the next guy will refine my directions a little. Have fun.
p.s.
Can't be much of a road to the coast north of Fortuna cause its on the coast.
It's true. This ride takes about 20 miles just to get to the coast, covering an "as the crow flies" distance of about two miles. :lol:
