My son returns from china (college trip) on June 3rd, so his girlfriend and I are meeting him in San Francisco. We want to stay a while since we have never been there. I know there are certain "must sees" that I want to do, but I have no idea how many days to stay. I have to figure this out in order to book my airfare. Is a week too long or too short? We have family there that we will have to visit, but we won't be staying with them. Can anyone give me a guess on how many days to plan? thanks