Traci,
Let's start with the weather. According to the National Weather Service, the Orlando area in November enjoys highs (therefore indicating how you want to dress for the parks) of around 79 degrees. It has lows (therefore how you want to dress for nights out) of around 58 degrees. And you are past the rainy season, so while you could get a wet spell, it is not as likely as those visiting throughout the late summer.
BOTTOM LINE: You are going to be able to wear summer gear during most days, but you have to have some layers if you are going to be out at night. Frankly, since the start of your day may still be in the high 60s, you really will want those layers at easy reach during the day. Sweatshirts, light sweaters, or something like that will keep the evening from being ruined with constant shivering.
As for
Mickey's Very Merry Christmas Party, it is a great event. Forget about all the activities for a second. The festive and warm ambiance exude an environment that can only be described by the German word "
gemutlichkeit". When I am strolling down Main Street USA, lit up and decorated for the holidays, I just feel cozy and happy. Add to that the great parade, the parties, the shorter attraction lines, and all the other bells and whistles, and it makes for a wonderful time, if you can afford the extra tickets.
BOTTOM LINE: If you can afford the party tickets in your overall vacation budget, you will really enjoy yourself.
Write me back if you have any follow-up questions.
Have a magical vacation!