Hi, Kathy! Welcome back to planDisney.
I love how you're starting off your party night just right. Dinner at
The Plaza Restaurant will set you up for success so that you can enjoy every moment of
Mickey's Very Merry Christmas Party.
Although the party doesn't start until 7:00 PM, Guests with a ticket to the event can enter
Magic Kingdom Park at 4:00 PM. You're correct that there can sometimes be a bit of a line to get in. However, I'd just encourage you to show up a bit early and explain to a Cast Member that you have dining reservations at The Plaza Restaurant. No Cast Member wants you missing that meal! There is also a 15-minute grace period for dining reservations. So I wouldn't stress about it, Kathy. It sounds like you're already planning wisely.
Here's a tip for the party: take advantage of the free holiday treats and snacks sprinkled around the park. From cookies to hot cocoa, it's a fun way to snack as you stroll Main Street U.S.A., or pop between rides. You might want to keep a small backpack handy so you can grab a few and enjoy them whilst finding your spot for the shows or
Mickey’s Once Upon a Christmastime Parade.
Merry Christmas, Kathy!
Mike