Wading River was the end of the extension just north of what state highway on Long Island?
Wading River (LIRR station):  This is an abandoned station just outside south of downtown Wading River, and was located on Wading River-Manor Road (former Suffolk CR 25) north of New York State Route 25A. New York State Route 25A: New York State Route 25A (NY 25A) is a state highway on Long Island in New York in the United States.
New York State Route 25A