I flat-towed mine to Goblin Fest a couple of years ago, and I used shrink wrap from in front of the cabin to behind the seats. It made it most of the 600 miles down and all of the 600 miles back in one piece. Some of the overlaps came apart on the way down, letting in some debris, but the little rain we encountered was kept out.
If I do it again I'll wrap from in front of the windshield to just past the steering wheel to keep the power steering and cluster dry.