bflat, I have taken instruments into schools a lot. My advice--take junkers. Do NOT let them touch your good guitar. Do not let them touch instruments unsupervised. Make them take turns--line them up and have one aide help you and the other mind those waiting a turn. If you can do one on one, that is great, but never more than 2 kids to one adult and instrument.

Guitars are difficult for small hands. I usually use 1/2 size violins, lap dulcimers and lap harps. Do not take any percussion instruments unless you want to go bonkers very soon. Uh, I know I will think of other stuff. Oh, stash a bottle of booze at home.....you will need it when you get there!