If you've got plenty of propane, I'd set the temp a little higher...say 50 or even warmer. It'll keep the house and basement (I'm assuming the Ventana has basement heat) well above freezing. Open the cabinet doors so the heat will get to the undersink areas. Maybe turn on the propane side of the water heater too. I don't know what the tank heating pads draw...I'm sure someone here can tell you if they'll operate on 20 amps. Propane is cheap compared to replacing broken water lines and damage therefrom.
Marshall Valentino, Beattie, TX
2019 Baystar 3124, CHF
2016 Chevy Colorado Toad, Blue Ox, RVi brake & Tire Patrol