Re the tarp: Tarps are now available in many different colors, not just blue. You can find camo and brown tarps most anywhere and I have clear tarps that I wrap around my chicken run in the winter.
I’m not an expert, but it looks like the van would only have ac like we have in a regular car. Wouldn’t there be a be a box on top or somewhere for the AC for campers? Also, the couple stated that the van seemed deserted, so I take that to mean that it wasn’t running. Would it be too hot to be “chilling” in the van with doors and windows closed?
The position of the shoes seem to indicate she took them off before getting into the van, and if she took them off to change into boots, for example, seems like they would be pointed away from the van.
I do see a book, which would be a strange thing to leave on the ground, and maybe a glasses case on top.
That location doesn’t look to be an ideal place to camp. It looks more like a little pull in with not much room to pitch a tent.