Originally Posted by 709
I'll second the hardboard recommendation for a project like this, or for extra lightness go with corrugated plastic board (sold in 48x96 as well).
I get the wanting to make it out of easily transported and smaller pieces, but I think you're going to run into creasing and unwanted folding if you go that route. A rental truck isn't ideal, sure, but nobody in your circle has a pick-up that you can buy him/her lunch for the trouble? The corrugated plastic and (to a lesser extent) hardboard have some flex… maybe you could even fit either of those into a larger Jeep-style vehicle.
I just moved here and literally everyone at my company (all four of us) drives a hatchback.