Are the stock doors removable like the Atlas 60' autoparts cars? If so you can use the door from a Life-Like X72 or Exactrail USRE 5277. I happen to have the sides of the Exactrail cars if you are interested. You would need to cut them to size and sand them flat.
Oh, and if you are taking those doors off... I would like them. Those are the Youngstown doors required to make my Mack DM800.