Up in Ramona (30-40 miles from La Jolla) they have a Fire Attack base with at least a huey and some fixed wingers, but of greater interest are some classic birds at a place called Classic Rotors, and they can show you around the birds on saturday or by appointment. Website is:
Also, at Motgomery Field (15-20 miles from La Jolla) the SDPD ABLE (AirBorne Law Enforcement I believe) unit is set up in the north-easternmost corner. The main lobby under the control tower has some friendly folks that can point you where to go. Pretty interesting seeing the 206 that started the unit, which was confiscated from drug runners.
At Gillespie, ChopperDr pretty much covered everything. There used to be an operator out there with a nice ole UH-1H with a big smiley face on the nose, Ron Walters was his name, but he's serving 20 years or so for drug running (sadly). If you want to check out some good fixed wing stuff, the San Diego Aerospace Museum has a big lot out on the north eastern part of the airport, and there are several hangar-based museums as well.
You can also check out Lindberg Field, the airport with the so called "knuckle departure" and building-hugging approaches. Its really somthing to see... get there about 5pm and you might be able to see the British Airways 747 come in (largest routine flight) and do it's thing... its so large, they have to shut down the airport while it taxies out to takeoff (it takes up the runway and taxiway simultaniously!) and give it a huge percession of fire and police vehicles. It's really somthing.
MCAS Miramar has a museum as well, with some great birds on display - most notably a 214ST captured from Iraq in the Gulf War. Nice bird!
Hope you enjoy your trip!