you know, something I've been experimenting with, but could never publish because the rest of the map failed, is putting to silos on the sides of the barn where the roof entrance is, putting an outer ring on the silo, and a pathway into the barn roof. Maybe to get to the silo you can make a building, which will also take away the negative space factor.
Just an idea that can be done with two cylinders and a sphere (make sure to func_detail the sphere)