Originally Posted by
raybo
If you want distance, then go all the way down to San Diego. But, the quality of the ride degrades once you are south of Santa Barbara (some would say south of San Luis Obispo). Certainly, riding south of LA offers little of note.
I have always been told that and stopped at San Luis Obispo, so I don't have first hand experience south of there. I especially liked Oregon and northern California and think October would be an OK time to go. September is my favorite time, but October is good too. I actually like the cooler temps, but October is a little wetter. Not typically bad, just a little wetter. By November it starts to get too wet to suit me.
If flexible, you might set your sights a little further north. If you aren't set on a particular start or end point you could choose any section between Astoria Oregon and San Luis Obispo and be guaranteed beautiful scenery. The Oregon portion was really nice. FWIW the riding can be more challenging than you might expect for a coastal route. It can also be more remote at times. I was really surprised when there were free range cattle on the road at one point. All in all a great place to ride.