It has been quite a while since I cycled any part of the PCBR. Check hostels in Seattle on Google. That might get you something. There were quite a few nice hostels in SF when I was there. I met a young woman in one who was extremely talented in speaking with different accents. She could do it just like a professional actress on TV, even better.
I remember it was quite hilly leaving south out of Stinson Beach. You come to a long descent after passing a Buddist center. The descent takes you to bike paths which go to or near the Golden Gate Bridge. I do not know why, but I had to carry the bike down stairs, go to the other side of the bridge, and carry it up stairs to cycle across the bridge. The state of Washington should be rainy. I had quite a bit of rain in Wash. and OR, but once in CA, there was not a single day of rain while cycling. It is an excellent ride with plenty of well wooded areas. The wind will come in from the quarter rear or rear and give you a good push at times. Entering Eureka, CA I remember some strong side winds, and that because I think your route takes you at an angle quite different from much else of the route. There are inexpensive state campgrounds with hiker-biker campsites along the way.