If I had three young kids I would add a tent to the plan so they can learn about some independence and give some separation between the adults and the kids. It is the way we grew up.
When the weather is bad, then the kids can sleep inside. I saw a trailer yesterday with three bunks stacked on top of each other made by Outdoors RV in Oregon. Bunk houses and toy haulers are a good idea. Kids are adaptable and can fit anywhere.
I grew up sleeping on a boat. My folks had the cabin and we slept in the cockpit. Sometimes we slep on top of the cabin. There was no air conditioning in those days and we slept on the boat 4 wekends out of 5 from May until October.