my husband shows me this:
Yes. It is a bunker.
To quote from the flyer, "It is the only private land for 12 miles. There are hidden caves which I will show to the new owner. These caves have not likely seen any humans besides myself and my boys."
Or how about this selling point "Step outside the front door and you can fire a pistol, throw knives, strip naked, whatever!"
You could even make this guy mad, with no negative consequences.
Forget charm, comfort and beauty. We're going for indestructibility. Really.