Previous post included: "When I de-winterized last Monday I did not drain the antifreeze from the outside shower, intentionally. All other lines were prepped for normal camping. Has been below freezing for the last 7 days. No issues so far."
Still no issues on the outside shower that was not drained of antifreeze when I de-winterized in December. I'm now in Colorado with temperatures down to 5 degrees F at night.
Temperatures for the next 6 days will be 41 F or higher during the day. Anything that might have frozen will surely thaw and show itself with these nice temps.
Lesson learned: Pull in the bump-outs at night. This significantly decreases the number of cubic feet of air required to be heated during the cold nights.