To avoid condensation on the windows, the dew point of the air in the RV needs to be lower than the inside surface temperature of the glass. With single-pane windows and cold outside temperatures, that means the indoor relative humidity needs to be less than something around 20% (depending on the exact temperatures involved), which is getting pretty low for one's comfort or health. In short, it may not really be practical to avoid all condensation.
That's not to suggest that you wouldn't benefit from some dehumidification and/or air exchange; it is very easy for the air in a closed-up RV that you're living in to get quite moist.
