My dear Rustic Rebel,

I apologize for relocating you to the the Lonestar State. I thought I remembered you saying that you used to run 'round nekkid on th' banks of the Rio Grande makin' pipes outta riverbank clay an' smokin' locoweed in 'em. I can't remember my own birthday, but my memory's usually pretty reliable where women runnin' 'round in their birthday suits is concerned. If that part of my ole brain's slippin' I guess I'll jus' go shoot myself.

Maybe "Vain" is just shorthand for that Vainom Kug town in Arizona. Sorta like all those 'Catters that live in Kingston Upon Hull over in England just call the place "Hull". Maybe Vainom Kugers just call it "Vain" for short. That would explain why Robert Johnson was so upset that all his love was in Vain. Probably couldn't afford a train ticket to go all the way from Mississippi to Arizona just for a little nookie.