it depends what dances she is teaching as to what songs will work for it:
good brown gravy by joe diffie works for the line dance "confusion"

copperhead road by steve earle works for the line dance "copperhead road"

don't be stupid by shania twain works well for the line dance "country walking"

here is a line dance site that lists dances and the appropriate songs to go to them:
http://members.aol.com/pbrown4715/dance01.htm