Over the decades we have camped at Big Sur when the kids, now 29 and 32, were out of school for winter break. We would borrow GrandPa's Southwind MH.
I don't recall using the heater. As long as the overnight low is in the upper 40's I probably would not leave the heater on overnight. I probably would use the heater to take the chill out in the morning.
But I was a lot younger then and probably could tolerate the cold better.
We will take delivery of a Solera 24R in the next few weeks. The first trip will be Big Sur in early December for the weekend.
For our current TT, I would set the thermostat to the lowest possible setting, which is about 55 F. I would set it lower if I could, but I can't so I shan't.
Wayne in Coarsegold near Yosemite
2013 Forest River Solera 24R
2014 Jeep Wrangler Rubicon
ATV trailer for the following toys
2008 Yamaha WR250R,2009 Honda CRF150F
2008 Polaris Scrambler 500