We are going the 14-20 because of Pop Warner crowds the week before. I don't think you have to worry about holiday crowds until the weekend of the 20/21st because Christmas isn't until Wednesday/Thursday the following week. We have frequently gone that week before the holiday, coming home the weekend before the holiday. Yes, we can see the crowds increasing that weekend, but still not crazy and we've already been to all the parks by then and are getting ready to leave on Saturday or Sunday.
Have fun making your plans!!