I wanted to provide an update on this project. We used two of the DIY spray foam kits on the walls. 1.25" foil-faced insulation on the ceiling, 2" pink foam board on the floor, covered by 1/2" OSB. There is a wall-mounted electric heater on the wall. The water line from the well and to the farm hydrants exit the wall and enter a 2x PT box that extends into the ground. Those lines are wrapped in heat tape to below the frost line. Here are some photos of the finished product:
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