What kind of Kempo, specifically? To my knowledge, there are no Tracy or EPAK schools nearby. John Sepulveda (EPAK) is down the peninsula a ways in Santa Clara, I think, near San Jose. Sepulveda may have a branch school in Pacifica, which is south of San Francisco a short ways.
Navarro's kenpo school is on Mission Street around 30th or so, his lineage traces thru William Chow, but not Ed Parker. I don't really know much about what he does, but I believe he calls it Chinese Kempo.
Ralph Castro's headquarters is just off Hwy 280 in Daly City, just south of SF. A student of his, Rick Alemany, broke away and established his own version, his school is in the Richmond District, out towards the ocean, on about 20th Ave and Irvine, or so.
There might be a couple United Studios of Self Defense around yet, but most of those that I was aware of have closed down. They are from the Fred Villari lineage, I believe. They always struck me as being very Business Oriented and never impressed me with their quality. I think there might be one left on Lombard Street, around Fillmore St.
I can't vouche for the quality of any of these schools, but this is what I know of.
Hope that helps.