I've been camping since I was 3 years old. I have memories of holding my infant youngest sister and feeding her while camping.
One piece of advice from my experience of how my parents worked with us:
The kids have been cooped up in the car for a long time. They need very much to move their bodies vigorously to burn off some of that pent-up energy. We were always charged with some specific task like: gather firewood, go to the country store and pick up something, find out how long it takes to walk to the beach. Something to just get us out of his hair while he was setting up.
In other words, set them free.