May I suggest making one or two "transition cars" with an F2 hook and horn coupler on one end and a knuckle coupler on the other. Then just use...
Southern premerger... I run a lot of NW cars on my layout which is premerger Southern primarly!
Don't foreget CRR A manifest from that decade would also include Clinchfield Railroad. I am in Asheville NC and a LOT of Clinchfield cars...