The Vicarage Orchard ~ Layout table upgrade progression

Super, look for “craft foam sheets”. Most craft stores sell it in 2–3 mm thick, and I presume about 6x9 or 9x12 inch sizes. You can also buy it in self-adhesive, which I sometimes found useful. I used it to replace or augment the foam padding in old toys (inside GI Joe helmets, for example) and it worked a lot better than the factory original stuff.

I think it’s the same material used to make things like can cozies and various other novelty items. Some big advantages over styrofoam is that it’s flexible and also resistant to solvent based paint. The downside is that it has less structural rigidity than styrofoam, foamcore or cardboard.