There's a bunch of fun trails (mostly unmarked) in Las Ramblas/Dana Hills, but you really need a guide to do it right. I don't live there anymore or I'd show you around.
I think those trails probably improved my riding more than any other Socal trails; there are jumps, gaps, steeps, narrow, flowy, sketchy/fun bridges, etc., pretty much everything except chunky gnar. And you can connect those trails to the Weedpatch to make a pretty big epic! Also, most of the trails are great on a SS--especially Two Balls and a Bone!