Dear Mike,
to become an idea what is possible with RAW files and converting them to B&W with Nik Collection (for Example) please take a look at
Robin Whalley dxo nik black - YouTube
or
Anthony Morganti dxo nik black - YouTube
(there is also a tutorial for Zone system ) Mastering the Nik Collection - 7: Silver Efex Pro 2 Zone Mapping - YouTube
and here is what one forum member does with an old, badly scanned jpeg from a friend of mine
Ans as I see…the photo of the falls by Ken was processed by an professional photo studio and implemented with split toning and,and, and … lot of work 
Enjoy