In Family First: The folks at "The North Face" have some backpack essentials for summer outdoor adventures.
First, bring a trail guide and journal, so children can see where they're going, and write it all down.
Pack a toy or Frisbee for down time, and energy snacks and water for when everyone gets hungry.
Bring lightweight emergency jackets for sudden downpours, and a first aid kit for any bumps or bruises.