There always was a door boarded up, so we were unsure what there was to find.
I'll tell you what we found (Well, the BOG. He's the one who did the work). Pretty much zero insulation. Drafty holes. Masking tape to cover such holes.
My neighbors borrowed huge boxes of skeleton keys. I need to spend some time trying to see if any work. I will, I've just been stacking wood and planting gardens.