If you're stationed at Camp Pendleton, you can take Metrolink or Amtrak trains from Oceanside to Anaheim, and it's a very short walk from the station to the Honda Center. I think if you go to a weeknight gane, you can take Amtrak back to Oceanside because it runs later. Don't go to L.A. They're mean. Ducks fans are much nicer (she says, patting herself on the back.)
Take care!