It sounds odd, but I needed (but failed to bring) one gallon zip lock freezer bags. I used the bags to keep things like maps, notebooks, and whatnot dry when in the field enviroment. You'd be surprised how moist things carried for days / weeks in your ACU pockets can get in the heat of summer. I also went through baby wipes like they were, well, baby wipes. As for treats, a good care package might also include hard candy that won't melt.