Here’s my latest solo multitrack project: Four Strong Winds, a song by Ian and Sylvia that was covered by other artists including Neil Young and John Denver.
I used Strum Machine as a backing track (using headphones) to record the lead vocal and guitar tracks in Audacity. Then, I overdubbed myself playing mandolin and ubass, and singing harmony, then mixed the tracks.
I created the Strum Machine chart myself. Here it is, if anyone is interested: https://strummachine.com/app/songs/hDNNaNnJ4k3nGfWdP