I love finding old images like this. They show that we never really change yet are on a continuum of adaptation. The bows that support the canvas top on this (I believe aftermarket) truck bed are reminiscent of much earlier wagons of the Old West.
Space was extremely limited in the cab of these old vehicles so if there were three on-board, I suspect someone, probably the boy, rode in back with the luggage.
Preindustrial Craftsmanship 
That is awesome. Early Days “Van” Adventures. I have often thought about a “pop up” camping trailer where the pop-up part is two end walls that fold up from the “wagon base” with “wooden arch bows” inserted in between with canvas draped over the top and secured at the ends with a drawstring and continuous looping across the bottom sides. Similar to boom tents on dinghies for dinghy camping on waterways (popular in England). Have you ever looked around the Library of Congress for other old camping type photos? https://www.loc.gov/collections/ It’s a great resource and the images by in large are free. Thanks for sharing this great image!
I think the classic 19th century “open lot” style wagon has solid ends and canvas top. It doesn’t fold though. As for the resource: absolutely, the Library of Congress and the Smithsonian are amazing resources.