We have special mattresses depending on the van to be camped. with the fit for the trunk area, and in accordion for medium-sized vans, and in small Rifter/Berlingo/Kangoo/Courier type vans, in a “T” shape to make the most of the width between the doors, and sleep comfortably.
We make the small campers with 6cm of high-density D30 foam, and the medium-sized camper vans have 80mm mattresses and a density of D25Kg/m³.
They always fit folded in the trunk of the van.