Claire, why don't you google - folkdj listserv - and join up for awhile. Read the playlists posted by various "folk" DJs and see which ones are apt to use your kind of music. The google response will let you click on the website, and also point you to an article written by Bob Blackman with suggestions for getting airplay. He's a tradition-oriented DJ in Michigan who works for Elderly Instruments as a day job. Good guy!

I hope Jed Marum will see your query and respond. He's done an outstanding job of promoting his own self-produced CDs. He could help, I'm sure. You might even send him a personal message, asking for his suggestions. Another good guy.

Good luck!