That's Neil and his first girlfriend, Pam Smith, at Falcon Lake, Manitoba in August of 1964. Picture = 1000 words, if not more.
You can read the piece over here. Lots of fascinating stuff, but nothing specifically -- alas -- about why Neil seems to have bailed on the Buffalo Springfield reunion tour, which is apparently now deader than the Papal penis.
Although this bit about a recent show with Crazy Horse...
He played that night as if he were mad at Old Black [his Les Paul guitar], even if he smiled into the squall. The crowd remained enthralled as he tortured a single note with the whammy bar, although this kind of indulgence has worn out some of his other playing partners. “We’ve played that note, can we move on, Neil?” Stephen Stills says with a laugh over the phone as he recalls playing with Young....may have some small relevance.