Hello, generally, the time period between Christmas and New Years are very busy. If you go right before Thanksgiving, you can sometimes miss some of the crowds. January and early February are the best times to go. In March and April, the rates tend to go up for both accommodations and airfare because of Spring Break and it gets busy (especially around Easter).

How long are you planning on staying around Disney World? There are several resorts on the property that are designed for longer stays and feature kitchenettes or even full kitchens, living room areas, and separate bedrooms. I've also had good luck with vrbo.com (vacation rental by owner). They have several houses listed for rent in close proximity to Disney (search Lake Buena Vista).

I hope this helps. Let me know if you want more information. I lived near there for 12 years and had annual passes each year. Thanks!