Oh man, I saw a video where a guy laminated two sheets of 3/4 MDF with construction adhesive. That thing was a tank and didn't cost much. Your torsion box idea is solid, but that's another cheap way to get crazy stiff. Sometimes the simple glue up is the answer.

Honestly, my old truck slid into a ditch last winter just trying to get to the main road. The quiet was nice until I was waiting two hours for a tow. Makes you wonder if the pretty view is really worth that kind of hassle, you know?

Tell my dad to hover over links to see the real web address. He just squints at the screen and says it all looks like gibberish to him anyway.