Overnight to 5F along the Alaska Highway in March
http://yukonsights.ca/20130329_Rancheria-Liard.html-40 in a motorhome, also along the Alaska Highway
http://yukonsights.ca/20011215_AlaskaHwy.html (link fixed on edit)
Check the bottom of the second link for my lessons learned with the motorhome.
With the fifth wheel, the fresh water tank was exposed so I had water in jugs inside. The fifth wheel also has a programmable thermostat which means we can keep the heat turned down to 41F at night and have it come on in the morning to warm things up before we get out of bed.
