We went in August of 2002 for 6 days before our cruise. I think, we were there from August 9th through the 15th. But not 100% sure. Anyways, I didn't think the crowds were too bad. But I'm from CA so what do I know about crowds. Anyways, we took advantage of Early Entry days. We also, stayed at the Polynesian and took breaks in the afternoon to swim (the monarail made that easy). Then, we'd spend the evenings at Epcot eating a yummy dinner. The humidity didn't bother me as much as I thought it would. But the rain was a pain. Most people said that it would only rain an hour in the evenings. Well, it would rain buckets for hours and hours. Luckily, we decided at the last minute to go to Epcot on our 1st night there to see the Illuinations. Good thing we did because the rest of the nights we were there it was cancelled because of rain. So, some of our evening plans had to be adjusted. We still had fun.... I should also mention that my girls are young so we spent most of our time at MK and AK with Epcot in the evenings.
HTH...