We don't do much cold weather camping, but have been out when temps fell into the 30's.
For our Aspen Trail 1900 RB we found that using a small 1500 watt box type fan heater worked but temp control adjustment was trial and error. Our propane furnace held the set temperature perfectly.
I broke down and purchased a plug in gadget (econohome model TH-926T)with a built in thermostat on Amazon. So we plug in the gadget and plug our electric heater into the gadget and set the temperature. This setup now holds the temp using the electric heater at the set temp "right on the money", allowing us to be comfortable using either propane or electric.
Safe travels and all the best..
