What is your budget like? Are you looking to splurge at one or more of these spots or are you looking for something inexpensive?
I am not sure what your plans are in SF, but we have stayed at Parc 55 before and it was nice, with a great location (close to union square and the mall). We don't stay there often because we live right near there. Beware of parking fees no matter where you book in SF.
In Monterey we like to stay at the Centrella Bed & Breakfast that is actually in Pacific Grove. The rooms are small, but the location is great and the breakfast and 24 hr. free tea/coffee/hot chocolate are great. The are lots of nice hotels though, and many B&B's in Pacific Grove and Carmel which would be close to Pebble Beach if that is what you are going for. For the B&Bs try checking their websites directly for the best prices and deals.
In Yosemite there are few options for staying in the park and all of them book up really fast so you need to book really early- you can camp, stay in tent cabins at curry village, stay at the Wawona hotel, the Yosemite Lodge or the Ahwanee ($$$). Another good option if you don't want to camp and can't afford inside the park is to rent a house at "the Redwoods in Yosemite" they rent lots of houses of various size and price range. It is not in the valley, but is up near Wawona/Mariposa. We have stayed in the house called "The Mini" there and it was tiny, cute and perfect for two people, but it is definitely a cabin.
Hopefully something here helped- have a great trip!
