Prep your black and grey tank dumps by pouring RV antifreeze down both while empty. The antifreeze will end up in the dump pipes and protect them from freezing. Roughly estimate the volume...perhaps 1 gallon in black and 1/2 gallon in grey, and that antifreeze will park itself right up against the dump valves and fill the pipes. The tanks are up inside and relatively safe. And the large cubic volume will prevent freezing for a long time...easily overnight.
Next, for dry camping (no fresh water in the plumbing, you remember tent camping, right?)
Get several Reliance jugs
and fill with fresh water. 7 gallons of water weigh 60 pounds (with jug). They make 5 gallon size, too. I usually fill my fresh tank (30 gallons) and bring 4 of the Reliance jugs in the bed of my truck (28 gallons). I can go 10 days without being all that frugal. While you're at it, buy a spare cap
and make an easy adapter to dump from the jug into your fresh tank. The cap has 1/2" pipe (NPT) thread. Go to a hardware store and get a plastic adapter with 1/2" NPT on one side and a barb on the other. Buy 18" of clear plastic hose and a hose clamp. This makes an ideal pour spout for filling your fresh tank. Never spill a drop.
Meanwhile, in the winter, you can use jug water for everything. Use dishwater for flushing. (you'll need a plastic dishpan...perhaps two: one wash, one rinse) Now you need not worry about the temps.
Just be sure to winterize with air...for dry freshwater plumbing...and leave your fresh tank and low point drains open so you don't crack the valves. I have a decent compressor at home (this is adequate
), and I can winterize the whole rig in minutes. Don't forget to dump the water out of the input screen on your pump, and don't forget to drain filters if you have them inside the rig. You're good to go with no worries.