I can tell you that we stayed at San Dimas at the East Shore RV Park. We have one of the best RV sites we have ever had. Of course, you will have to drive almost anywhere you go in the Los Angeles area, but if you want to take the RV and can get in Loop A I would highly recommend East Shore.
BTW,our friends live in Glendale, but we found the drive to be worth it to stay in the kind of site we had. Being out East/South of the city meant that we towed the RV in and out without taking it "deeper" into the city. We did all the other driving in our tow vehicle.