Well if it was me with a wife and 2 kids, the boy I would make a a bag for him nothing to heavy, maybe flashlight,bottle of water,granola bars, rain poncho, comfort items, favorite candy and stuffed animal etc. The wife and youngest I would use a large duffel bag, with clothes, food water etc. and also include items for the boy. Then for myself I would have a quality backpack with gear such as radios,snares,signaling,knives etc. things you wouldn't want the children getting hold of.

I'm just tossing out a few ideas, I'm sure others will either agree or disagree and have their own suggestions, read it all and sort out what works for you.

Hope some of it helps.