I respectfully disagree with klayfish that touring plans information is based on snake oil and voodoo. They use as scientific a method as is possible to try to predict human behavior. It's far from perfect, and it can obviously be affected by weather, unexpected changes in hours, and rides breaking down, but they're right more often than they're wrong. And few people will take the time to go to their website and read their extensive explanation of what the numbers actually mean. They just assume that a 1 means there's no one there, when all it means is that it is one of the least crowded days, crowded being relative. But I think it's pretty much a given that a party day at MK is going to be significantly less crowded than a non-party day, because most people will choose to go to MK when it is open late, rather than have to leave by 6 . We have gone to WDW in early December for many years and have found this to invariably be true. Non-party days are very crowded, and party days, while hardly deserted, are much more manageable. If a non-party day at MK is the only time someone can be there, it can certainly be navigated fairly well with some really good planning. But, given the choice, I'd take a party day at MK anytime.