We are from State College, PA and we have gone the last 2 years during our Spring Break in early March and each time the crowds have been managable. In fact, we are going again this year and look forward to it.
However, the National Cheerleading Championship will be March 10- 13. If you don't mind cheerleaders walking around the parks, then you will be fine. The weekend will probably be a little busier during that time.
Have fun on your trip!