Hi Erin! When my daughter was younger, she sooo needed her sleep, so I totally understand!
Mickey's Very Merry Christmas Party is a special ticket event at the Magic Kingdom. When the clock strikes 7 pm, the park closes for regular guests and is open to party ticket holders only. I used to think it would be a quieter day at the Magic Kingdom given its early closure, but this past November was proven wrong, as the park was packed the day of the party. I've been surprised so many times, that I finally concede that I can't predict crowds!! Disney has come up with a brilliant solution: the Park Hopper! The
Park Hopper Option allows you to visit more than one park in a day. That means if you visit one and it is too busy, you can hop on over to another park!
Another way to maximize your theme park time and avoid crowds is to get there early, about 15 minutes before opening time. This will allow you to get through security and hit the ground running! Although the entrance may seem very crowded, you'll be surprised at how the people disperse in different directions, and you'll be amazed at how much you'll get done in the early hours!
Wishing you a magical vacation Erin!