Good idea or not?

Just to give you a background of my unit, I own a 2006 Perma-Mount 120 Deluxe by Bane Clene.  So I was thinking of the most effective way to keep from freezing while not using a ceramic heater or spraying my brand new E-250 with insulation foam and came up with an idea of a tarp and a thermal blanket. Now before you all say I got an idea pull in the garage....  not so easy, the thing is way too big for an everyday sub-division garage. That said, I do plug in the water tank over night and the water stays around 160-200 degrees in the 120 gallon tank. The tank does put off steam through a tiny hole in the cap on top of the tank, which made me think if I could try and trap some of the steam, I would not have to use the ever so dangerous space heater. Obviously I am not concerned with the actual water tank freezing, rather the lines and the pumps, etc. So what do you think? Good idea? Please only useful comments, thank you!!