IMHO, there are only a few select weeks during the year where one can say it isn't crowded. I only experienced that once during the first week of Feb. If you read up on info and know when to go to what parks on what days and how to structure your days, you should have no probs. As for heat, I guess that is just part of Florida! Dress cooly, drink lotsa water, take a pool break in the afternoon, and there you have it...a great vacation!