Have winter camped in two Northwoods. Previous Nash and present Arctic Fox. Both have dump valves inside the heated compartments for the tanks. Been very comfortable at 0 and slightly below. It helps a lot if it gets above freezing during the day. I use the water system but do open cabinet doors at night. I stuff the outside shower compartment full of insulation. Have factory made storm windows on both which really helps a lot. Have never used skirting but imagine it would make a significant difference. Skirting does not seem very practical unless you are staying in one place for the entire time you are using the TT.
