John & Holly (Frazzled)... and anyone else in-the-know!
I saw your post re traveling to the NW corner of our perty country for the Winter (Wow! have a great, safe trip!) and tried to private message you, but I can't see that it worked, so rather than hijacking your thread in the travel section, I am posting here.
I may be delayed in cold weather before I can flee south. Like you, I live in my rig, so I am looking for PC-specific tips on keeping the plumbing safe in freezing weather while living in it. Most of the tips I find on the web apply to winterizing for storage purposes. If possible, I would like to be able to have access to my plumbing rather than shutting things down. I am not talking sub-zero temps, but I would like to be confident to survive the 20s for a spell.
I understand I have heat pads for the Gray and Black tanks, and that the FW tank and most of the plumbing is inside, but I am confused about the things that are outside, how vulnerable they may be, and what action I should take. Please know (if you don't already), I am a total noob and need layman's explanations.

Re the outside shower, do I simply turn the faucets on, with the water pump off, to drain whatever is in there?
Re the macerator, if I put antifreeze in the gray tank and then don't drain it out all the way when I am done emptying the gray, will that protect the macerator and it's connections by allowing some of the antifreeze to sit in there?
If I keep antifreeze in the black and gray tanks and do not empty them all of the way, will that be enough to protect them, along with the heating pads?
Re the hot water tank, do you leave it on overnight to protect it from freezing? Does it draw so much electricity that I would be in danger of tripping a fuse when the furnace came on at the same time?
If I am driving in freezing weather for a few hours, do I need to worry about things freezing? Should I (can I?) have the propane furnace running when driving?
In the outside storage drawer, to the right side, there is a cut out in the wood which gives access to the drains (hot, cold, and ?). Are those vulnerable to freezing? Even though they are under the bed, I imagine the fact that they are open to that outside storage bin can make them vulnerable.
Are there any other points where the plumbing comes outside that I need to watch or address?
Thanks!