Opinion on winterability of my rig

Pnichols: thanks for that thoughtful and thorough response. Very good point about running the furnace I hadn't thought of. Yes my furnace is ducted so keeping it running can only help keep everything around those ducts in the floor warmer. I got the heating pads that are powered either by AC or 12v because I thought that gave me more options, for example so that they would work when I'm driving. I did also get one of the pipe heaters which I am putting in the center of the long run between the Grey tank and the dump valves. However they only make that one in 12v and I don't know if I'm going to be able to get that connected by Friday when I leave because I have no idea how to route that at the moment and was just planning on using the plug-ins this weekend.

Also I installed an AC element to my hot water heater today and it works great. I think that will help a lot since I can keep it running all the time once i get to the campground and plug in