My wife graduated with a batchelor's in music and is asked regularly to volunteer in the local grade school. This year she went once a month (rotating with three other volunteers) to fourth grade, even though our fourth grader is being home schooled. Anyway, they use the Silver-Burdett text and CD set. It seems to focus quite a bit on folk music. She will sometimes look for different versions of the songs and bring them also - for instance, she took in a recording of "Cindy, Cindy" by Pete Wernick to let them hear some good bluegrass banjo and the kids really liked it.

So volunteer - the teachers will love you, you won't cost the taxpayers anything, and you can expand the horizons of kids and expand the curriculum to include something you feel is important.