There is a fairly new location off the Interstate 5 Freeway, called I-5 Self Storage, located in Tustin, CA. You can see it off the freeway near the Jamboree off ramp.
The website is http://www.i5selfstorage.com
At the Grand Opening last year, there were a lot of nice cars, and they have several options, both indoors and outdoors. There are certain areas that you can view on a website to potentially see your car, if it is stored outside. And there are about 25+ video cameras and individual access codes. There are reviews on Yelp! too.
They accept vehicle storage from individuals and also businesses.