I would check with touringplans or some of the other crowd predicting sites.
Only schools in the northeast have President's week off. We have lived in Louisiana, Florida, Virginia, Illinois, and now Texas and have never been in or near a school district that has a week off in February for any reason.
I do realize that a lot of people do have that week off, but nowhere near the entire country.
The week before and the week after Easter are the most crowded of all of the Spring Break weeks. However, schools have their breaks spread out between March and April and most do not coincide with Easter.
Still, Spring Break can be crazy at WDW.
HTH