All this talk of Arlo makes me think of Woody, which makes me think of Billy who'll I'll be seeing here in a couple of days. If you're a fan of either of the Guthries and haven't already done so, check out the two Mermaid Avenue albums. Billy Bragg and Wilco were asked by Woody's daughter to record some of his songs that had been written but were never recorded. There's some absolutely beautiful music on both albums. Here's one.
https://www.youtube.com/watch?v=vwcQAlRn0Gs
EDIT: helps to have Natalie Merchant singing backup :)