I moved to San Francisco from the Midwest in 2009. Like you, I made sure I endorsed to a California RN license and certificate to practice as an NP. My most important advice is to never make arrangements to move unless you have a firm job offer. Hospitals in the city and the surrounding area have career websites and it's easy to navigate through job openings. I happen to find a job as a nurse practitioner just by looking online. I do have years of experience from the Midwest and the job opportunity I applied for perfectly suited my qualifications. I am saying this only to warn you that the job market in San Francisco and the Bay Area is saturated with many well qualified applicants so don't feel less worthy if you don't get calls right away.
Now on to living in San Francisco which is a unique city, unlike any place in the US I've ever been to (though it has qualities you will see in other cities outside the US). One, the city has an overwhelmingly liberal political ideology. You will see that in the way the city handles issues pertaining to public service, city and county ordinances, social services, etc. It is extreme and having considered myself a liberal, I am still at times shocked by what I see here. Two, even though it is a tightly compact city (and county, really), there are distinct neighborhoods that actually bleed into each other. Housing is very expensive as you already know but the trick is finding that neighborhood that suits your needs in terms of budget, the lifestyle you want to live, and the proximity to where you will be working.
I found that apartment hunting is not an easy task here. One, there is competition from other would be renters especially in desirable neighborhoods and good apartment deals go away fast. Two, without being intimately familiar with the neighborhoods in the city and your preferences as far as qualities in a neighborhood, you could easily end up in an area you hate if you don't do your research beforehand. Fortunately, craigslist seems to be the most extensive source of available housing options you can have. The listings can be arranged by neighborhood and by price range. If it's any consolation, you do not have to live in the city to work in the city. The Bay Area itself has good options with good public transportation that can bring you to your work in the city.