You've been given a tall order - to play songs strangers will know.

1. Plan A: ask the organizers for some suggestions. Then alternate songs with your Cape Breton tunes.

2. Plan B: visit Contemplator's Scottish page and look for good tunes. If you know some of the tunes there, chances are others know them.

http://www.contemplator.com/scotland/

3. IMHO, these are Scottish songs everybody knows

The Campbells are Coming
Loch Lomond
Where oh, Where has my Highland Laddie Gone?
Scotland the Brave
My love is like a red, red rose
Coming through the rye
Flow Gently Sweet Afton (tune written by an American)