That's an interesting topic, as I did ride the Chessie ferry from Ludington to Kewannee and back from Manitowoc to Ludington. The passengers were boarded first, then the railcars, then the autos. The ferry dock at Kewannee didn't have facilities to unload autos from the second deck, so only as many autos as would fit amongst the railcars could be loaded.

I'm returning home from Wisconsin, staying overnight in Manistique. Sadly, the hotel desk clerk couldn't tell me where the carferry dock was in Manistique from when there were ferries from Northport to Manistique.