Winter Camping in Mache ?

After doing the math and attempting to get as many possible new england ski days out of my pass this year, it looks like ski bumming it up in the mache is my best bet to be able to afford to do a trip every weekend.

Anybody have experience winter camping with the mache, mainly using the heater over night in 10 or 20F temps? Mainly, what precent of battery ill be using to maintain a 60 degree cabin tempt overnight. I plan to park near fast chargers or stay plugged into a LV2 overnight if I can.