full timer 5er noob looking for some expierenced advice

Our last two fivers have had "Artic Packages", and this new one has that plus "full timers package" and the most insulation you can get, minus the double pane windows. I don't think there are any RV's that can consistently handle really cold weather. We do a month or so of 25-35 degree temps each year but much longer or much colder and there could be problems.