I rode through the redwoods this past October and November and I can highly recommend the section off of highway 101 that goes through the Prairie Creek Redwoods. Not much traffic and it is beautiful. Also, ride the whole Avenue of the Giants. You will not be disappointed by this road either. If you are up for more of a challenge, the Lost Coast is another route that is extremely beautiful, but much much more challenging that the others that I have mentioned. Also, on the lost coast the services are further between and more meager, but if you are up for the adventure don't let that deter you.