One correction that I'm not 100% sure even is a correction!
But judging by comments I've read on an NYC Yahoo group (with many former NYC employees and mostly pertaining to the 1960s) the KD jobs did work all the way to 72nd Street but they were based out of the Yonkers yard which was KD. For Putnam Division traffic they often placed cars for pickup by main line freights near Spuyten Duyvil or sometimes at the Yonkers yard. They worked in reverse delivering loads. There was also a job based at Kingsbridge (FH-1) that used to place or pickup cars at BN for the Put and switch the yard there. FH-1 also made trips to Westchester Avenue.
In earlier (busier times) eastbound road freights used to drop Put loads between Kingsbridge and BN on Track 2 and westbound empties went on Track 1. They were handled by FH-1 or one of the KD jobs. In the 1960s DM-2 (the Dewitt-Westchester Avenue Yard meat train) sometimes dropped A&P loads directly at BN, shoving them into a yard track.
All of the KD and FH trains were traveling switchers by agreement. Meaning they were assigned to a specific territory and could perform multiple tasks within that territory.
At least back in the 1960s the crew for BNBO reported for work at BN.
Happy New Year to all the NYC Forum folks!