Crowds always vary at these parks. Once, I went to Cedar Point on a Tuesday in June and it was packed. I got to do everything but lines were around an hour. There will be crowds in the middle of July, but hopefully you'll get lucky.
Sorry but I am going to Six Flags Worlds of Adventure for the first time this summer, so I can't really help you out with them.
-------------
Spring Break- IOA,BGT,Magic Mountain,Epcot,MGM