Ahh welcome to MN (soon) I am sure we will eventually meet at club event eventually, maybe.
I don't know what type of rental van you will be using but Dave is reminding us that most moving trucks are made to be a little modular and can be outfitted for a specific task. Most all will have a metal bar with notches going around the walls of the trailer so that cargo can be ratchet strapped tight to walls, if you can't drill into the walls of the truck maybe you make a larger bench/brace/box and then secure it with ratchet straps to the wall.