Does, or maybe it did and it has fully closed, Wallpack Center open for a holiday schedule for exactly like OP is seeking in getting that unusual post mark?

Not NJ but close- Bethlehem PA post office does nicely designed canceled stamps. They're all about Christmas out there.

Hmm, I thought they stopped all operations in the ‘80s?

Thanks for this, I need to mail some postcards from Batsto!

BUTTZVILLE, NJ 07829

Not too far of a drive should take you about 45 mins to and hour depending on where in Morris you are from. Go grab some Hot Dog Tommy's right on Route 46 (along the Delaware River).

Grover’s Mill, location of Martian landing in Orson Welles live radio broadcast of War of the Worlds. There is a plaque commemorating the event and a nearby diner that is full of memorabilia.

There is a post office in Ben Franklins house in Philly. Part of the museum essentially.

https://www.nps.gov/places/b-free-franklin-post-office.htm

Mizpah, New Jersey, if it's still open.

Been closed for years. I believe their mail goes through Belvidere now.