To travel full-time with 6 kids we needed a way to provide beds at night, but floor space during the day. We considered a standard 5th wheel bunkhouse, but those beds are on the short side, cramped, and require special bedding for the odd sized/shaped mattresses.
We settled on a Grand Design Momentum 398M-R as it’s the only camper we found that has 2 sets of HappiJac beds, giving us 4 queen sized beds in the garage area for the kids to sleep in. Since sharing a bed can be annoying, and we already had twin sized mattresses and bedding we modified the stock queen beds to support 6 twin beds. We later modified the remaining queen bed into a giant shelf. By using our existing beds we were also able to bring our existing bedding from home, which gave the kids an anchor to make the transition to life on the road a little easier. It also gives each of the kids a small space to customize and call their own.
The pictures below detail the sequence of how we constructed the bottom bed frame and the lumber we used. For the top twin beds we simply used bunkie boards from standard bunk beds and screwed them into the top bed frame.