We went in May 2011 from a Tuesday through Friday (one of those nights was a grad night). Tuesday and Wednesday were wonderful, the longest waits we had were for Go Go Gadget Coaster and Dumbo and they were about 20 min. (The longest lines we saw, but did not go on those rides, were for the Matterhorn and Midway Games which were both about 45 min long). Thursday got a bit busier (it was the grad night) and on Friday it was busier than I liked. I have never been during the summer to compare crowds, but the waits on Friday were so bad we only did a few rides and just walked around and got more autographs, left midday to swim, and came back for the fireworks.
We went later in May, probably closer to some schools being out, which might explain the crowds later in the week. I think with the dates you are going the crowds won't be bad at all. Have fun...