I posted this to the wrong thread before. whups Anyway, I just walked into the military surplus plot. The counter is a bit too close to the front wall, but that's not really a big deal. When I was done trading with the NPC inside, I backed up to go out the door, and backed right through the wall and outside again. None of the walls of this building nor the ladder upstairs has any collision. The counter and the door do have collision as well as other items inside the building. but the walls themselves do not.