LED lights make a bigger difference than many realize.
If you are REALLY boondocking, a trench shovel with a roll of TP on the handle for all daytime needs.
I find that running the furnace a short while just before going to bed and a nice heavy down comforter allows us to turn the heater WAY back at night. If you have a digital thermostat, set it to run for a short while just before you get up. That way you can get undressed, sleep, and get dressed in the morning warm with little furnace time.