I'm tempted to make this four stars, but I'll leave it at three. This is one of my favorite local roads, and for reasons that even I find it hard to explain. This road can be used to get from Hwy 101 in either Marin or Sonoma counties out to Hwy 1 in Marin along Tomales Bay. It connects with Hwy 1 north of the worst of the Bay Area traffic, and it then leads along a really pretty section north to the town of Tomales, famous for its bakery.
It is rough in places, but portions of it seem to get repaved every couple of years. It's a bit technical in places, but not terribly so. It gets quite a bit of bicycle traffic on the weekends, and a few sightseers, but for the most part overtaking is easy, and lots of drivers pull over to make way in any case.
The bottom line is that the road can be a bit of a romp. Not really a racer road, and not a goat trail, but a fun, lightly trafficked way to get to the coast.