Greetings Jennifer!
Guests with recreational and oversized vehicles are welcome to park in the Mickey & Friends Parking Structure as long as the vehicle doesn't exceed the height limit of 13'10".
This would allow you and your family to visit the
Disneyland Resort theme parks and
Downtown Disney District and return to your camper for a break or a nap on the day of your visit.
At this time, however, accommodations for overnight parking are not available at the Mickey & Friends Parking Structure.
If you're looking for overnight
parking near the Disneyland Resort, I am certain you can find an RV Park nearby through a simple online search.
I've heard of at least one place near Disneyland where guests can catch public transportation to the Disneyland Resort.
I hope this helps. Thanks for stopping by the Disney Parks Moms Panel!
-Anabel M.