D->E is not as interesting as it seems on a map, speaking from personal experience. I strongly suggest you head south into Colorado, then into Utah, maybe dip into Arizona to see the Grand Canyon, then head north to the Seattle area and head back south to San Francisco taking the US-1, which is some of the world's sexiest coastline riding imaginable. This includes Eureka->San Francisco along the US-1. Stay near that coastline as much as possible. Don't skip out on any of Colorado, Utah, or that northern part of Arizona. It's some of the most unique terrain in the world and well worth the detour down. Wyoming/South Dakota... meh, just waypoints between where you have to be and all the interesting stuff, I say!