Congrats on getting all of the work done that you are reporting in your update!
Sorry about the overhead doors being on backorder. Stapling a big plastic drop cloth on the exterior door frame and another on the interior frame should help you retain some heat. Maybe that will be enough to get by with a shop heater running since you will almost certainly have a few hard freezes by mid-November.
What are your warming parameters on the well water? (Current temperature, water rate, and target temperature). Surely the PB crew can spitball some ideas!
Are you looking more for "poor-boy" solutions like a DIY solar pool heater, or considering spending significant money for fool-proof system like a natural gas fired heat exchanger with thermostat?
