Survived 7 degrees, gusty winds from NW in Raton, NM in March a couples of years back. We were parked north to south. Water lines were insulated in fresh water compartment and shore water compartment with 75 watt bulbs turned on through the cold and snow. Compartment doors were also insulated with the silver looking "bubble" stuff as previously mentioned. Left water dripping (grey tank open) so that water still flowed to prevent outside water spigot/hose from freezing. Fridge access compartment was also insulated and wrapped. Learned from experience---lost the ice maker valve in prior cold......$100+ dollars to replace part only. Pics attached.
Pete and Patty
2010 Georgetown 378TS; 2012 4dr Jeep Rubicon
1 Yellow Lab (hers);1 Little Bitty dog (mine)