We've done the cereal bars, but a lot of them have nuts as well. Certain cookies are good too. We have always avoided M+M's as there are peanut M+M's as well. However, his allergist showed him how he can do his own scratch tests with a toothpick and the food in question, having benedryl cream and an epi pen handy. However, I specifically do not recommend this for other people-see your own allergist before attempting any such thing. In any case, it turns out that he hasn't had any bad reactions to M+M's. So that's a good new possibility.
So, I can get the sugar and carbs into him. Now to find the protein. String cheese, maybe. He likes gogurt, but I think that would have wait for a supermarket stop, as there's really no way to keep it cold during a tour. The manufacturers mostly all use nuts/peanuts for protein. Ahh-I just thought... Beef jerkey. He likes that.
So just flushing this out has reminded me of good possibilities, so thanks to all!