Off-grid Winter RVing Question

Add a second battery and charge with the genny in the AM before you hit the slopes and in the PM when you get back. With the second battery you should be able to get thru the night with a combination of the coach furnace which should heat your tanks and your portable heater. Recharging the batteries the next AM & PM and you can go on like that for many nights. We typically run without the water system, but still use the toilet and the bathroom sink with bottled water for washing hands and brushing teeth. If we do run the water system for showers, we leave the furnace on at the lowest setting. LED lights too. Have fun, and it is always exciting to wake up to the avalanche guns.