[Festus2]

I wouldn't rely too much on the "Polar Package" to offer much in the way of protection against pipe and tank freeze up in prolong periods of freezing temperatures. Don't forget that you have to have your furnace running in order for any warm air to make its way through the 2" duct to the underbelly and tanks/valves. The moment the furnace is off the supply of warm air to these areas is also "off" leaving them unprotected.

Another option to consider is to use a plastic, portable wash basin and/or sink instead of the regular sinks in the kitchen and bathroom. Use the plastic dish pan for washing dishes and another one for the bathroom sink. If you use the shower...... well, that's a different matter. Have an old-fashioned "sponge bath".

You can improvise and "rough it" and not use the gray water tanks at all. I guess it depends upon how much in the way of convenience are you willing to do without.