I took my 6 year old son on an overnight hike with the cub scouts to sleep in a cave a few weeks ago. He took a basic adult school backpack with a change of clothes, his sleeping bag and his bulky sleeping pad. He's a little guy for his age too. It was probably 10 lbs. The hike was about a mile in. He did fine and never complianed about his pack at all. In fact he ran and moved much faster than me.