I hope this keeps to your theme of hearing from people who successfully heat their coaches. My apology for not elaborating on my first post. For me, the OP was not clear as to what your need is. Too your credit I have put the link, in the OP, in my HVAC folder. One never knows when this might fit my needs. I guess I should have mentioned this earlier, just to provide you a measure of confidence that your post was read and carefully considered.
I hope you don't mind, but another solution has been successful. For me, at this time, I will stick with it.
If one wants to increase the size of their propane capacity, go to
Mr Heater Corp - Stay A While Deluxe - Propane Hoses and Adapters - Camping World
and read about this product. I've used one of these for years. It works as advertised and I would make the same purchase again. In the winter I carry 2 20# bottles of propane in addition to a full coach tank.
If one wants to keep your batteries charged, consider purchasing a small generator that runs on gas. To run just the battery charger doesn't take much generator power. The small units will run a very long time on a small amount of fuel.
As to those whose teeth are chattering not posting enough to satisfy you, maybe there aren't that many who camp like you do or worry, as much as you do, about this topic. A variety of solutions are available. Unfortunately, there is no free lunch. One needs to choose a solution that fits their needs and determine their own business case.
While the thread was started by you, several members have done their best to post what they thought was a valid response. In addition, one never knows who reads the thread and might pick up valuable information, even if the post may not have provided an answer the OP wanted.