IIRC the last time any freight occurred on the Coastline south of Red Bank was the late 90's/early 2000's. There was Builders' General in Little Silver, which still has the switch there + was the last customer on the Coastline south of Red Bank.
The other last customers were the Asbury Park Press somewhere in Bradley Beach (there's a part of Memorial Drive there that the pavement is arranged in such a way that it covers their old siding tracks), a Lumber Yard in Belmar (which until recently, you could still see the rails in their facility), and maybe or two other businesses further south than that