I generally fly at Whittier (Just got back from this morning, in fact), but there is also the Sepulveda Basin area in the San Fernando Valley.
Basically at the intersection of the 101 and 405 freeways. Go north on the 405 to the first exit, Burbank Blvd. Turn left and then right at the first opportunity, Woodman Blvd. Go north about 3/4 mile and there is a turn in to the left. Then backtrack south to the flying area.
Both Whittier and Sepulveda have CL and RC activity. Saturday is often dead at Whittier, but if you give me a call, I can probably make it a point to be there. e-mail at [email protected] or [email protected] and I'll give you my phone numbers.
Trostle and Wright45 are also frequent denizens of Whittier. Even TonyG has been known to be dragged hither on a Sunday (if you promise him a big dose of Ether).