Winter RV camping

In the winter of 2010-11 we camped in NH with no snow for any extra insulation. Temperatures got to -15. Fridge worked fine with ice cream in it. We were pulling electric from our own meter so I had only one extra infrared heater we used sparingly. I had a 100lb tank filling between 1-3 weeks depending on temps. I didn't connect water choosing to fill the tank and use the pump. When draining the gray and black I chose the standard method, black first then gray with electric valves and had no problems. We kept the temp around 66. Can't wait to go skiing one of tuese winters out west now that we know everything works.