Lake Central Airlines (formerly Turner Airlines, later bought out by Allegheny) plied my part of the Midwest with P&W-powered DC-3's. Some were converted C-47's, some were prewar DC-3's with a RH pax door.
I once rode one fresh out of the shop, and I still remember being impressed how quiet it was. (and across the aisle sat Stan Getz on his way to a gig.)
There's still a fleet of freighters operating out of Hook Field, Middletown OH (six visible on Google Earth)