I'm in the same boat. No knob and tune, and all the plaster has been removed as well (thankfully by someone else in the houses lifetime).
I've also DIY installed 3 mini split units in the house -- the last one being an AC / DC unit that directly gets powered via 4 panels on the roof during the sunny moments of the day.
Built a new addition 3-4 years back. It's far better insulated than the main structure, but the wood stove and heat pump combo keeps winter mostly at bay.
