I'm sorry, but there's lots bad information in this thread. First of all to the OP you should consider doing a search of the forum for San Francisco. There has been quite a bit written about the area already. Consider going to the archives (over a year old) for helpful threads too using "Advanced Search".
With that being said, there are much cheaper (certinaly than $1,600 a month) options in the Bay Area. You need to forget about the peninsula and concentrate on East Bay. I started out staying at San Francisco RV Resort for ~$1,400 a month with all utilities included along with WiFi. That was the most I ever paid to full-time there. This resort was right on the ocean, and trust me there are older rigs than you're considering in that place.
In east bay, there's Trailer Haven in San Leandro where you can stay for ~$700 a month,and it's minutes from the BART. Also, there are a few mobile home parks that will accept RVs in that area. Do yourself a favor and do a little research here and on Yelp for more information.
