SE - we don't need cooking or toilet facilities, just a couple of bedrooms
and an open area (the mobile is just for 2 kids' bedrooms - everything and
everyone else is in the building next door).

I wouldn't even consider using one for kids bedrooms without toilet
facilities. If you don't have them, you're going to have a lot of wet sheets
and mattresses to clean. The difference between having a bunk or a standard
bed is large enough, without having to get dressed and walk to another
building in the middle of the night to relieve themselves.

Christian.