Gdetrailer,
I do not compromise on comfort.
A candle does about 80 watts. 600/80 = 7.5 candles. Tea lights only do about 40 watts.
But then a 1500 watt heater only does 18.75 candles.
The "usual" furnace on an RV is about 5862 watts.
My load at -10 c (14 f) is about 2000 watts with a peak of 2400 and a low of 750. In theory I could use the hybrid setting on the Magnum remote to allow me to use a 15 amp shore power for those loads.
On Oct 14, 2016, my 24 hour use for *all* heating tasks was 3.3 kwh. (water heating, cooking and space heating). I used the hybrid inverter and limited my demand to 1440 watts and plugged into a kill-a-watt meter.
I do have the OEM power cord, and two auxiliary shore power cords. I have pretty good luck finding two outlets on different breakers. Three is a bit harder but still possible at some locations.
At -27 C (-17 f) my peak load goes to 7100 watts and the average is about 4000. That includes running a block heater for the car. At those temperatures I need 3 15 amp circuits--or a 50 amp with a "break out box".
The electric bill goes up by about 24 cents an hour at -10 c (14 f) where I live. It is easy to offer the folks, who are providing power, $10 which more than covers the costs. Or if you want to be stingy $5 still covers the cost.
I prefer to take them out to dinner. It costs more, but fellowship is important when you are single.