Here's a great set of aerial photos of Disneyland from the 1960's. I would guess 1965 or early 1966 based on the work I see with Pirates and Small World, but its just a guess, its not like a have a compendium to look up such things, ah but I wish I did.
Originally I thought these were the same photograph, with one just being a cropped version. Upon closer inspection it appears these photos were taken at different times, maybe just moments apart as most of the parked cars seem not to have moved, but the Mark Twain has moved.
Here's the close-up version. You can download a high resolution version with the link below.
Disneyland Aerial Photo - 67mb
This is the large print and it has lots of detail regarding the surrounding area. Go to Google Maps, type in Disneyland and have a field day doing comparisons, I did!. The park itself hasn't change nearly as much as the area around it. Well, both have actually changed a lot! You can download a high resolution version with the link below.
Disneyland and surrounding area Aerial Photo - 30mb