We have a 2021 Grand Design Momentum 398M-R. We chose the model because it is the only toyhauler we know of that has an 18′ garage with 2 HappiJac bed systems, giving us four queen beds to play with. We’ve done extensive modifications to the beds and now have 6 twin beds and one gigantic shelf.
This gallery provides a current view of the setup, but it’s continually evolving.

Set up for school
The backroom setup for school. We also eat indoor meals at the table when the weather doesn’t allow eating outside.
Beds are up during the day. At night the front beds only come down as far as the laundry basket. The rear beds stop at the greige(tm) bench.

Front beds down
View of the front beds down from the kitchen door.
Berkey on the left, washer/dryer on the right.

Top view of the front beds
The front beds are down for the night. Showing the space between the twin beds (14″, about 12″ usable), and distance from the ceiling.

Front beds from the side
The front beds are down for the night.
Showing the storage shelf underneath. You have to duck walk underneath when the bed is down. The shelf is a long queen size.
The stackable washer/dryer are peeking through in the background.