Bart Royale: Crafting

Do the battlescape and/or house frame do anything? I think that, for the first time in all the years I've been playing, I might actually skip crafting a couple of items from the selection.

I focused on crafting tunnel pieces as the most efficient way to get to 20%, but I may be regretting that slightly, because the fences would have more potential for reusability, once I store most of the ugly stuff (like the main battle area) from this event.