We have a 40' DP bunkhouse. Works great for us and our 2 kids that are now 13 & 10.
They each have a large drawer under the lower bunk for clothes and share our wardrobe closet for coats and such. They usually sit on the couch which has lap belts or in the dinette which also has belts. When we stay up later than them watching tv we just close the first door between the hallway and bunk area. I built an extra cabinet in each bunk for them to store their stuff. I would never go back to anything other than a class A. Sure beats having them cramped up in the backseat of a pickup.