Here's an idea for you.
If you're down by RIV, you may be in a good place to pick up Empire sector of SoCal, let alone Feeder for the rest of the approach sectors. If memory serves me right, Feeder should be on 124.05. You'll definitely hear what the handoff freq is from the Riverside or Barstow Center sector controllers on 126.35 or 133.75. It's been a while since I flew down the Hector corridor to the L.A. Basin, but I'm pretty sure the 124.05 frequency is the one. If so, you may be in a good spot to provide some pretty solid SoCal feeds!