My spreadsheet has a calc to find the $/oz that pays off the mortgage on my house.
But after some thought, it might be better to default on this house in a few years, and use the hoard to buy a different house at a lower Ag cost. Its quite possible that real estate has another price crash coming up. Why sell the hoard & pay the mortgage off, only to loose all that value?
And then there is the possibility of liens attached to any house, where its not likely the hoard can have a lien against it, if it can be found.