I've always been impressed by Tom Rush's having recorded songs by Joni Mitchell, James Taylor, and Jackson Browne before most people had even heard of them.
By the way, did Joni Mitchell ever put Urge for Going on an album? I remember hearing a recording of her doing it on an "underground" radio station (WDAS) in Philadelphia in 1970, and I have an even vaguer memory (ginkgo deficiency again) of finding it as a single on a jukebox in a restaurant in Princeton in 1970 or 1971. But I'm pretty sure, even without ginkgo, that it wasn't on any of her early albums.

Aloha,
Mark