Originally Posted by squrlgurl
I am thinking about installing a heater mat under the black tank (we live in the Mid-Atlantic with cold winters) and possibly heat-wrap around plumbing elbows.
Your black tank is heated by the furnace. You should have a heat register right in front of the toilet area, which has a provision to circulate heated air around the black tank.
Which makes updating the plumbing at and around the black tank an even better idea. Imagine a tiny leak from teh black tank, and then the hot air circulating the odor into the trailer. Eeeww!
I further suggest to update the dump valve flange, so that a modern dump valve can be fitted. I did not follow your links above, you might have this one already taken into consideration.
But then, since you're already almost there, why not add a grey tank, at least a small one to enable having a shower or washing up while underway?