It is good to know that "All Through the Night" and The Ash Grove are from Welsh roots. Good luck with your project, and I hope the Smithsonian Folklife Festival goes well. When and Where is it to be?
www.folklife.si.edu/center/festival.html
The Smithsonian sponsored some festivities at a local museum centered around the development of different types of food in different ages.

They hold a National Folk Festival, this year's one is in Butte Montana.
I guess this video is of a regional festival, not the national one sponsored by Smithsonina...http://www.youtube.com/watch?v=3e9vqx8ujjY
here is the national smithsonian one in Butte MT, july 10-12 2008
http://www.nationalfolkfestival.com/ It will be held there for 3 years
2008-2010 (Alice will you be involved??!!)