There's even wonderful pockets along the CA coast. The Lost Coast has many awesome roads, paved and otherwise, that have little to no traffic and the few motorists I have encountered there have always treated me well. Parts of Hwy 36 and a few other east/west roads to the coast have similar conditions, if a bit more traffic and less steep hills.

If you want to avoid issues, just roll the forest service roads in OR and CA. I can ride many hundreds of miles on mostly paved roads with small gravel connections in the coast hills near my house with less than a car every quarter hour going by. When traffic is that light, many motorists stop to make conversation and ask directions, since they assume (usually correctly) that I know where we are and how to get to whatever site they were looking for.