@mimico_polak just to give you some ideas about a custom rig using your dads van as a base, here you go. Each kid can have their own room.
EDIT:
Just in case anybody wonders, the engine is in the cradle under the man-door on the white trailer. The wheel there is a trailer axle to try to help you avoid getting high-centred and stuck.
EDIT:
Just in case anybody wonders, the engine is in the cradle under the man-door on the white trailer. The wheel there is a trailer axle to try to help you avoid getting high-centred and stuck.