In 2014 I rode a bus from Amtrak station in Portland to Astoria, that bus stopped at other coastal communities before it got to Astoria. In Astoria there was not bus staion, just a stop. We found a cardboard recycle bin behind a nearby pizza place where we discarded our bike boxes. It was late evening when we got there, we had made reservations for a motel there. I know that is not the specific community you want to go to, just describing another option. There was a hostel in Seaside if you are looking for a low budget place to stay if you get there late on your first day.
In San Fransisco we stayed at the Fishermans Wharf hostel. Great price, but they do fill up so if you want to stay indoors on your last night, it would be best to make a reservation first.
A few comments on my trip that may help you in your planning are at this link:
Southt to North Pacific Coast Highway Concerns