Are you looking for California beach culture (La Bamba, Hobo, Nevison casual) ...or hollywood culture (think of the Hollywood sign or movies, Terminator was mentioned above, just think of other movies and their styles) ...or retro drive-in/diner (Letraset Harlow & Frankfurter) culture? Or maybe a more "casual sophisticated" wine country look (you fill in the blank here!)? What I'm getting at is it really depends on what your theme is. Palm trees (though they are not native to California) are a common theme in a certain southern California look and I'm sure I've seen a font that incorporates them along with other beach icons. No single font is going to cover it all, so many cultural trends have started there. The internet is a perfect place to get a feel for California culture...just start Googling..."In-N-Out Burger" for example, to get a feel for things.