Yep, It is a big issue with a 601 or the "inside" compartment of anything that is not insulated from the outside skin of that compartment AND you want to warm the inside warmer than the outside, "be it" a snow-cat, car, house, trailer, etc,etc. Unless you insulate the inside, or create a "vapor barrier" you will always have a condensation problem when you heat the inside AND there is snow on the roof, with NO snow on the roof the condensation problem will be very little if any.
That is the short and simple definition of condensation, the diff, between inside & outside temp, the surrounding dew point, relative humidity, and the type of heat being used also determine the amount of condensation or the lack of.
