We've been to WDW over 35 times and to me any information regarding crowd levels is just a crap shoot. We're there for such a such time and we go to the parks in any order we like. We have used Birnbaums in the past but now we just about wing the trip. We have our do's and must sees and like touring according to our likes. We've never encounter any problems, we do a park in the am, never at rope drop and leave when the temps get really hot or crowds close in and return to our resort, do DTD shopping, catch a movie, picnic and swim at our resort until evening when the temps and sun ate lower. We always go to a different park in the evenings and try to catch the ending show, if the park for the evening is rather packed, we just hop to another one, EPCOT is usually a good evening park, well spread out wide walkways and we exit at the IG to play around the Boardwalk area, Jellyrolls, Beaches and Cream or ESPN Club and either bus to the MK from there or return to EPCOT and finish our tour and monorail back ro our resort.
To me, those susposed books and charts are some well founded guess work but are published from averages of past years, no telling what convention, tour group or expedition of guest could be in the different parks on any given day to clog up the works. Thats why we either have park hoppers or AP's to scoot to a less crowded park. We'll never spend money on a guide, we like doing Disney our way and its about to each his own as to whats crowded or not, some people are only in the world for 3 or for days and that too hard to use a guide book on when to do where. Alot of people say skip the EMH's, not use, we go, if its packed, usually not we just leave, same with evening extra hours, 3 extra hours late at night is the best no matter what the crowd size. WE don't have to ride anything, just like to be in the parks, go in shops etc, crowds are no problem there.