A few years ago I attempted to make a small layout out of card board (corrugated paper). It was going to be a simple figure 8 under and over. It was going to be built totally out of card board. I gave up on it because I couldn't find large enough sheets of card board. Also cardboard from different manufacturers is different thicknesses. Places in the cardboard where folds occurred also caused irregularities when I started to assemble the layout. It was just a test to see if it could be done. I haven't exactly given up on the idea, but not a high priority at the moment.
Go to a store that sells moving supplies...like u-haul...buy a king size mattress box...nice and new corrugated cardboard...clean, flat and uniform thickness...
Howard..