My family spent 9 days in the parks last year during the Presidents Day week because we had a nice long break. Yes, it was crowded, but the crowds were manageable, in part because the weather is not hot. That is big part of making the crowds really miserable. Actually we had some rain on our trip and we loved it, as it got rid of everyone! Some of our best riding times, I tell you. Don't be scared of scheduling in this time frame. Be smart, use fast pass and good touring strategies and have a great time.