I was advised to take an alternative route, as well, and instead rode along the Washington coast. I kept track of route (link here) and wrote a journal of the ride I did from Bellingham, WA to Newburg, OR (journal here). On the route I did, there was a long stretch from Raymond down to Cathlamet with fewer services, though enough to do without any real worry.

Your timing should be good as the Fall offers some of the best weather on the California coast. There are a couple spots where planning will be required to insure that stores or restaurants are open for food. Specifically, the stretch from Carmel, CA down to Cambria, CA along the Big Sur coastline. While it is beautiful, some of the campgrounds may be closed or without potable water. Also, some of the villages along the coast offer a single place to eat that might be open only a few hours in the off-season.

It is a wonderful ride. Have a great time.