Depending on your out side temperatures I would not be overly concerned with the tanks. We had a 2005 Mirada in the UP of Michigan that we ran for a lot of AAU basketball tournaments and unless you were pushing 10F or less for a good chunk of time we did not have much of an issue. The only time I recall freezing up was in Ohio with lots of wind and that was the actually the lines inside along the bottom of the bedroom wall. Took the cover off and a hair dryer did the trick. Since then we carry fresh water in jugs in the coach and use it for flushing and heating up for wash water.
