If you plan on takeing several cold weather trips try this....
Once you blow out the fresh lines for winter leave them dry.. Do not use the fresh water system.. instead carry some 1 and 5 gallon bottles of water INSDIE the RV.. 1 gallon = recycled milk/juice jugs.
Use a 15=30 cup percolator to heat water for washing dishes and such.
Then, when you leave the park "Re-winterize" by dumping waste tanks, pouring some Pink into the drains and toilet and empty the jugs.. Very easy.
Oh, normally I'm anti-chemicals in waste tanks save for H20. but in this case I'd add a biological (Waste digester) the action of these products tends to be exothermic (they generate heat) not a lot, but every calorie or BTU helps.
When I left Detroit on Jan 2 2006.. That is how I did it till I got to warmer latitudes. Worked great.