It's quite normal these days to find restored Machinery trucks, radio vans and GS trucks at MV events fitted with a camper interior in the back......
a pity sometimes for the vehicle fanatic.......but the attached pictures show that this was done in 1944/45 as well!
Picture1 Amsterdam source:
https://www.nederlandsfotomuseum.nl/
Picture2 Den Haag source:
https://noord-hollandsarchief.nl/
Picture3 Utrecht source:
https://hetutrechtsarchief.nl/
Picture4 15cwt's were also used ....Ede source:
https://noord-hollandsarchief.nl/
Picture5 Another 15cwt. Barneveld source:
https://www.archieval.nl/resultaten.php?nav_id=1-0