Piru is by Magic Mountian, I-5 North then hang a left.
Prado is in Chino, 91 and the Corona Expressway. This is the '84 Olympic site. The facilities are still in tact and open.
In San Diego, the Oceanside Shooting Academy at I-5&76 (last Sunday) and American Shooting Center at 52 and 163 or I-15 have IDPA.
Oceanside has casual matches on Thursday nights mostly steel. Once a month a shotgun match.
If you'd like some other matches try IPSC and shoot Production or Limited. The USPSA website has schedules. Between Norco and Pala/LDF (San Diego) you can stay very busy.