That is exactly when we are going. All of my research says it will be just based off of the Disney posted hours of 8 - 12 (and it being the week after Easter.)
That said however - it will not be as bad as the summer or dec. holidays.
Plan well and all should be ok. Just be prepared for crowds.
The hours they have during that time are their busy hours, or summertime schedule. So I would plan on heavy crowds. Disneyland is fun whether it's crowded or not...you will have a great time. You get out of it what you put into it