Great thread, hats off to the OP, and great comment above, Buftex.
Just to help out the younglings a bit, after Thurman Thomas and OJ Simpson the third all time leading rusher for the Bills even given his limited time here is Joe Cribbs (I believe about 4,500 yards).
I still to this day don't think he was used as much in the pass as he could have been because he had great hands.
If he doesn't have a contract dispute and doesn't run off to the USFL he could have ended with about 8,000 - 9,000 yards rushing for this team and more than 400 grabs.