(I am from NJ) I have done 3 1-week trips during Jersey week, and have never had a problem with crowds.
I also spent a week in the summer before, and that was a vast difference in crowd size - give me Jersey week anytime!
You will notice a slight increase in crowds on the Wednesday-Sunday weekend, as most of the NJ schools have off the Thursday and Friday due the teachers convention - this year it is November 10-12.
That weekend is usually Super Soap weekend in MGM too - just avoid the areas where the soap stars are, and you will be fine.
-Joe