When in april 2016 to travel

northeast states passover week april 25 -29, public schools off, should i go april 20-30, which is booked, or change it a bit to april 16 to april 26,?

Depending on Easter, WDW Spring Break weeks are pretty much March through April. It runs a good 6 weeks. That being said, Easter of 2016 falls on March 27th. Early. So you actually might be OK with your late April dates.

i guess the later the better, thanks