While not the CNJ portion, I have encountered the W&W on the former WJ&S/PRR Cape May Branch south of Millville Yard but before Manumuskin Junction, where they store cars on and leading to the Leesburg Secondary Track from Manumuskin Junction to end of track at Port Elizabeth and, of course, on the the former WJ&S/PRR Cape May Branch between Menantico Wildlife Management Area/Wolf Crossing to end of track about a half mile south of Manumuskin Junction between 7:00am and 8:00am. I do not think they have a regular schedule south of Millville Yard at this time as there were no online customers. That said, the last time I dropped into Menantico WMA for a hike the W&W had pulled the WJ&S/PRSL era jointed rail and was installing new rail. I've never gotten a clear explanation as to why the W&W would do this for a branch with no on-line customers, but I did get speculation they were preparing for an online customer at or about Manumuskin Junction on the Cape May Branch or the Leesburg Secondary Track. I haven't been back down that way since early fall so I don't know where things stand at this point.
I know it's not on the CNJ, but if you dig photography of sand hoppers and tanker cars, or industrial relics once served by the PRSL and WJ&S, the hike south from Menantico WMA parking lot to Wolf Crossing isn't terrible and there are several nature paths that run parallel to the ROW. Just northeast of Wold Crossing is a variety of relics, foundations, etc parallel to the ROW that are walkable along existing roads and paths.
Interesting note, on the north side of the ROW is a stone obelisk which marks the Millville city border. It's a 19th century relic, but it looks complete.
Ed
"In Friendship, Love, and Truth"