Why not raise some money, and hire the Strasburg Rail Road to build a reproduction? The SRC car shop can build a copy from the rails up that John Norwood himself wouldn’t be able to tell from the original. I doubt that it would cost that much, considering its small size.
That would allow an authentic caboose to be available for endless charters without so much concern to its well being, saving 0503 for special occasions.
There have been many threads at this sight regarding the future need for replica engines, this could be an opportunity to try the concept on a smaller, and less expensive scale.