Workingman's Dead and then American Beauty both came out after the live album Europe '72, so it's safe to say they date back no further back than '73/74/75.

Deep Elem is, or at least was, in Dallas.

Besides the Bear's Choice album, Libba Cotten's "All Around This World," "Deep Hollow," and a few other such folksongs also appear on the regularly-released double-album called (I think) Dead Set, which included one all-acoustic LP and one all-electric, both recorded live during a tour when they opened every date with an acoustic set.

Well, the two guitars, at least, were truly acoustic, the electric bass was turned down fairly quiet and distortion-free, and the drums were played with brushes. I'm not sure if they trucked an acoustic piano around with them ~ the keyboard might have been moderately electric, too, like the bass.