We were there this year from April 14 to April 20, the week leading up to Easter and it was definitely crowded! I would say it was not quite as crowded as when I visited during March spring break in 2010 but it was close. We found it got busier and busier as the week wore on. However, my cousin went during April vacation a few years back when it was NOT close to Easter and loved it. They had great weather and really reasonable crowds.
We have been contemplating another big extended family trip in a few years, decided between 2014 and 2015 and we are leaning towards 2015 when Easter is not near April vacation.