We don't winterize, as we like using all the utilities the TC has during the winter. It sits between trips in a heated garage. I made the choice of a gasoline fueled Honda EU2000 vs an internal, propane fueled Onan because of my intended use of the TC.
My favorite season of the year is winter. The problem with winter camping and winter activities is that it is very unforgiving, especially below 0 degrees. A gasoline fueled generator is a good backup to provide electrical heat, if a propane issue develops as mentioned in a post above. You might reconsider carrying a gasoline generator if you decide not to winterize.
If I had a propane fueled generator taken down by the same issue as the propane fueled furnace, our winter down bags would save us, but they wouldn't do much for our TC plumbing, tanks and valves.
Emergency winterizing is a backup, if you have enough RV antifreeze. However something to consider when using RV antifreeze (50% propylene glycol) and other freezing point depressing chemicals is: the amount of freezing point depression is related to the concentration of the chemical (molality of total solution). See the table below.
Using one volume of chemicals for every volume you put in your tanks affords some protection, yet using less than 1 part of chemicals per 2 parts of volume in your tank only lowers the freezing point to the 20's F, not much protection. Using -40 windshield washer fluid affords the most protection (45-50% methanol) as it is diluted.
