The book Neil Young: Long May You Run: The Illustrated History
says that this song "was likely more indicative of where his [Young's] head truly was. Much like the songs from the Springfield's debut, 'Mr. Soul' suggests that Young's work was still razor-sharp, even when it was coming from a very unhappy place."
While we're book-hopping, there are some ties between Buffalo Springfield members and Al Kooper (of Blues Project / Blood Sweat & Tears fame). In Kooper's memoir Backstage Passes and Backstabbing Bastards
, Kooper consulted with David Crosby when the idea of Blood Sweat & Tears was forming in his mind, and also recruited Jim Fielder (Frank Zappa and the Mothers alumni), who also part of Buffalo Springfield when they were seeking a replacement for Bruce Palmer's continuous absences. And then Stephen Stills himself popped by to fill in for Mike Bloomfield when Kooper, in a panic, called him to help complete the album Super Session
. There, is that enough threads weaving everything together?