What I will avoid are the tracks heard regularly on classic rock and oldies radio. I'll tend toward more or less obscure artists, occasionally throwing in less known tracks by well known artists or maybe sometimes live versions of well-known songs.
Addiss & Crofut were never big stars and are forgotten now. I have found a little information about their lives after their career as a duo for both Stephen Addiss and the late Bill Crofut. There is more information about both in the lengthy liner notes for their Folkways Records release.
Simple Gifts is the first song on their 1967 Columbia Records debut album. (The entire album is available through that link.) It was written in 1848 by Shaker leader Joseph Brackett and has been recorded by many artists since Aaron Copland reintroduced it to the world.