The last time i was there i met a lady who was camping. There is nothing on site but it can't be too far away. She was doing her laundry in the Disneyland hotel laundry room. I would check Woodalls. I LOVE Disneyland, can't wait to go back some day.
There is a campground just down harbour blvd. south. It is not what I would call a real campground. It is more or less a paved area with parking spots. My sister and brother in law stayed there our last trip. I don't know what we would have done with a trailer. There was no room. They had a truck camper and it just fit in their spot.
Last June we did a cross country trip and Disneyland was the only place we stayed in a hotel. We did the Grand Californian as a splurge. What a treat. We went through the valet parking and my DH drove the motorhome to a parking lot at the Disneyland Hotel, then was driven back by the valet.
It is a great destination. I wish we were going this June, too!