When we had our NB in Ireland it was suggested we put newspaper over the carpets to help nullify the effects of the more humid climate there when we left it for the winter.
With our barge in Burgundy, where it is not unusual to have temps of -15 I ran the water down to below half turned off the feed at the tank and ran the pump with all taps open until air came out. Drained the gas water heaters and left the drain plugs out, put anti freeze down the sinks and toilet and drained the mud box. When arriving back in the spring turn on valve at the tank replace drain plugs in heater and then start pump until water came out of taps whilst checking for any leaks from joints.