Hi Joe,
I love
Mickey's Very Merry Christmas Party (MVMCP) and you will too!
When I arrived, I would get settled in my hotel. I'm not sure where you're staying but your resort may have some fabulous holiday decorations. Because you're going to go to the Magic Kingdom for MVMCP, I'd get ready and head over to the Contemporary Resort to check out their Christmas decorations.
From there, I'd hop aboard the resort monorail and head over to the Grand Floridian Resort. They have an amazing Gingerbread House in the lobby that is made from edible materials by the Walt Disney World Food & Beverage Team. Although no nibbling on that house is allowed, you can purchase yummy treats from the shop inside the Gingerbread House - pretty cool.
I'd then head over to the Magic Kingdom so that I'd arrive in time to make it to my dinner reservation. Be sure to have your confirmation number on hand along with your ticket to MVMCP.
I'd save swimming and Downtown Disney for another day during my trip. Touring the resorts along the monorail line will put you in the area you need to be in for your dinner reservations. That may start your trip off less hectic and put you in a festive holiday mood.
Wishing you minnie magical holiday memories :-) Allison