Northern California coast roadtrip recommendations?

I will be driving down from Oregon as far as Ferndale (in Humboldt County), then spending the night there before continuing as far as Gualala. I'll go through the Redwoods National Park on my way to Ferndale and would like to stop for a hike but am not sure of the best places. I know there are also gorgeous beaches to stop at, but again, not sure where. Also would love recommendations for a hike between Ferndale and Gualala. A friend recommended the Eel River, but I don't have any details.