As for leaving from Orcas, either route would be good, though the Anacortes route would be easier (IMO).
Generally biking the west coast is a pretty straightforward affair. Like magic, there are campgrounds at reasonable day distances with nearby towns for supplies. Hard to beat. It bears repeating that checking out www.crazyguyonabike.com and search for the ACA Pacific Coast routes will lead you to journals that well describe the region.
Santa Rosa, CA