Hello everyone. So we just came back from a 2-night winter camping trip to the high desert west of Mendoza to a spot at 3000m of altitude to see how ready we were to cope with cold temperature at night. There is no heater in the camper, unless we are plugged in to a source of electricity.
During our upcoming trip to Peru and Bolivia we will be several times in very isolated areas and will have to overnight in the cold, without a source of electricity i.e. no heater. We brought one wool blanket, two fleece blankets, and a winter duvet. Thanks for following us!
Sin Rumbo 
Looks like a nice trip!