Congrats on a nice unit
Cannot answer some of your questions, but, can tell you that we have never run a de-humidifier, what we do is open one of the ceiling vents about 1/2 to 1 inch, and leave it open 24/7. If you steam up the windows, then add a fantastic vent or max-air vent to the mix and pull out the damp air for a while. Must run a vent when you shower or cook. After about 2 or 3 days of sitting in one campground, we find that the unit is nice a toasty warm and not overly humid.
Now, humidity may depend on where you are staying, etc. etc. etc. Personal habits, cooking habits, all that good stuff.
When we late fall or early spring camp, we have been known to go without water. OR, use the pump and on board fresh water storage, disconnecting the hoses and be sure to run the furnace. By running the furnace you force some warm air down in the belly of the monsters and unless it goes below 20 for hours and hours, or days, you won't have a problem. A dip into the 20's for a few hours is not a huge problem.
Others who have done some serious cool weather camping will be along to correct me or add to what I have said.
Have fun!!
