Hudson Highlands in NY.  We didn’t quite make it to the top since it is a tough hike for a 6 year old.  But we all enjoyed the challenge of hiking a section of the Breakneck Ridge Trail which was practically vertical.  You were always stepping up.   A strenuous hike, and probably not a good choice if you have bad knees.  The view from about 75% of the way up is stunning.  It was a new experience to look down at the Hudson River from somewhere besides a bridge.  We hope to go back and make it to the top, and possibly complete the entire 5.5 mile hike.