I don't see anything about this car that would tie it back to the Quincy & Torch Lake caboose/coach #4. The iron work is different, the car body is longer in length, the windows are are a different style & differ in number. I don't know of any other Q&TL coach stock, but with all of the narrow gauge lines up there, there is a very good possibility that a car body or two from one of the lines made it through time as a shed. The trucks may have been built from parts or old trucks in a railroad junk pile. I know of a couple of very early standard gauge wood passenger cars that last into the 1980s/90s as sheds around here. So there could have been something left up in the Copper Country to be the basis of this car. Perhaps the road name and the #24 are correct for what survived. The car though is a least a very heavy restoration to rebuild probably.
Dave