When you say that you're going to be off-grid 90% of the time, do you mean without an electric hook-up? Lack of shore power adds to the heating challenge at low temps because battery capacity limits how much you can run a typical RV furnance. Solutions include more batteries, catalytic heaters, running the genny a lot, covering all the windows with insulation, closing off the cab area from the house area, and so on. We inadvertantly spent several nights in the 20's in our 24' Minnie with no prior preparation. We ran an electric heater continuously. I think Earthroamer uses a diesel fired convection heater.
