The true outlet malls are outside of LA and DL area....there's Desert Premium Outlet in Palm Springs, Camarillo Outlet, Ontario (CA) Mills Outlet Mall (a mix of outlets & regular stores).
there's citadel in la. although they don't have much stores, or good ones! (for me personally!) that one's just off the 5, maybe 35/40 minutes away from dl.
camarillo is good. that's where i'd go, if i'm outles shopping! it's approximately 2 hours away from dl.
depends on what kinda shops you're looking for too...they pretty much have everything...if you need a specific store, or are looking for specifi things, maybe i can help?