Hey Bruce,
Joy to the World, and Oh Come Little Children are fairly easy to play on the box. Another one I play, not for sure on the name, but I hear it on the country radio stations, Christmas Time A Coming.
Instead of using a T-fer you can use bells, they make a hand held handle with multi bells on it, or use both may sound good also. Good luck!
MarkS
So far I've got 14 I'm working up and my daughter playing on guitar and singing some of them. Sounds pretty good. Playing the octaves is easy, but some of the single notes are a little tricky. But I've only been at it about a week and they are coming along just fine. I figure if I can master Christmas songs, I should be able to play about anything that comes my way. Bruce
A few years ago I heard a Sammy Kershaw version of "Christmas Time's a Comin'" with Cajun accordion, check it out if you can find it. Probably Wayne Toups playing, I'm not sure, but he did a lot of sessions in Nashville. A really good tune.