The high school the children go to in Harrington Park is Northern Valley Regional High School located on Central Avenue, Old Tappan. It is a Blue Ribbon school system and well recognized by most colleges in the Northeast.
The extracurricular activities are one of the best. Many different sports are offered as well as Clubs, theater, etc.
If you are interested in looking at homes in the Northern Valley area I would be happy to help you out.
My cell is 201-803-2617. All the best!!