Hi Barbara! Wow we might see each other at Mickey's Very Merry Christmas Party on the 19th! This is a great way to start your holiday vacation at Disney!
Most of the attractions will be open that evening so you can basically review the descriptions on the website to see what interests you and your children. Since you have four about the same age I suggest you allow each one to choose their own "must do" attraction to fit it into the evening plan. They will love having a part of the planning process and you will find less arguing. Once you have all the selections check out a Magic Kingdom map and plan the route you prefer to take. Crossing back and forth in the park is not a good use of time and energy!!!!! Some of the favorites include: Big Thunder Mountain, Splash Mountain, Space Mountain, Buzz Lightyear, Peoplemover, Laugh Factory, Pirates of the Caribbean, Small World, and Peter Pan's Ride. Of course there is so much more so take the time to read through the descriptions! Please click
HERE.
I suggest you try to stay as late as possible as the crowds will diminish greatly once the fireworks show is over. During the first parade time hit the attractions as you can find curbside seating most likely very easy for the second parade of the night. Don't miss the fireworks and in front of the castle is a great spot. Don't worry about it being crowded as you will be watching up in the sky for the most part so all views are pretty good.
Of course make sure you walk through the snow falling on Main Street and stop in for cocoa and cookies at some point during the evening at one of the many locations that will be well marked!