This was excellent--so rarely do "odd" crossovers like this work, because the author generally Mary or Marty-Stu's one of the universes.

There were many bits I thoroughly enjoyed--like Dean & Vimes, and the outsider POV on Carrot--but my favorite was Dean & Granny Weatherwax. She's always appreciated a straight shooter, and when Dean cuts the BS, he's a very straight shooter. (And props for finding a great way to *not* include Death!)