I'd like to chime in with my experience on the PCR. I found the Washington State part to be different--neither coastal nor mountainous, but rolling hills in agricultural land. Not spectacular, but pretty. It has more services, campsites, and motels than the coastal area, which may be why ACA chose it.
The ACA maps are the best in the world for cycling in my opinion, which seems to be the unanimous impression here. We supplement them with state road maps--low cost or free and readily available--when we want to go off route. Search the forum for "maps" to read many opinions and descriptions.
I'll recommend a side trip to Yosemite National Park. Arguably the most spectacular scenery on the continent, it is two days' ride each way through the flat, boring California Central Valley, but definitely worth every minute. It's a valley of 1 - 1.5 km width with vertical granite cliffs on both sides that are 0.3 - 0.8 km high. If El Capitan were laid on its side, it would fill the valley.
You will meet many rock climbers at the hiker-biker campground, as this is the Mecca of North American climbing. Run a Google Images search on Yosemite to get some idea of the place.
Highlights of the PCR for me: San Juan Islands in Washington (ride up Mt. Constitution for great views), the Oregon dunes (up and down over 150m - 300m headlands), the coastal redwood groves, Yosemite, and the Big Sur coastline. September is a good time to be there, after the crowding has abated.