John and all,
We are a small group and carry liability and equipment insurance through an agency located near Ithaca NY, True Insurance Agency. I know the rates are very reasonable or we could not afford them. You can find them on the web.
ASCAP should not be an issue as most of the music is traditional and does not fall under their umbrella, you run into issues with them if you have performers playing other's music without permission or if it has been copyrighted and registered with ASCAP. At least that is my understanding from working with a Blues NFP group and having been the manager of a restaurant.
Mary