We went last year during the week of Columbus day and it was very crowded. I have typically gone only during the April school vacation week and I am sorry to say it was more crowded during the Columbus day week. I dont know if it is like this every year though, but I was disappointed in the amount of the crowds. Last year however there was an amazing military discount which may have added to the additional people. It was a deal that was so hard to pass up and I am sure many took advantage of it.
As for the weather, the first half of the week was extremely hot and humid but I kept hearing that this is not typical of Oct. The second half was beautiful--middle to upper 70s with NO humidity!!!
Have fun!!