For a low-prep single overnighter, our family usually ends up with these as the final contenders:

SNACKS:
-crackers, cheese and jerky/pepperoni
-celery with peanut butter
-apples
-grapes (frozen in a ziplock bag the night before)

LUNCH:
-PB/ hot dogs/cheese in wraps (Condiment up the meat and cheese for more flavour! A mini can of salsa and/or jalapanos, sauce/ketchup/mustard from fast food places work well. Take-out jam and honey work well with the PB.)
*OR*
-can of baked beans or stew

DINNER:
-KD with hotdogs/pepperoni/tuna and sweet snap peas if they're in season. (Works with rice too! Make the powdered cheese sauce with powdered milk and margarine. Marg pepper, hot sauce, etc. from fast food places)
-cucumber and baby carrots

DESSERTS:
-marshmallows or some other roasted treat
-choco chip cookies
-peanut m&ms

BREAKFAST:
-COFFEE
-granola, or instant oatmeal, made with hot chocolate and raisins or dried cherries/cranberries