I do not actually winterize my unit until the first week of Jan each year. During Oct, Nov & Dec I just drain the lines/tanks & leave all faucets open between uses.
I also un-winterized in the beginning of March every year.
I run beach through the lines, flush a second time with fresh water, drain the lines & tanks & again leave all faucets open.
Never had a problem over 20 yrs & four campers.
We’ll be heading out for the first trip of the year next week.
If you follow this you should really not have a problem even if the temps drop for a short period of time.
Dave, Judy & Daisy May
2010 Sierra 356RL
2011 Silverado 2500 4WD, LT, Ext Cab, LB
Duramax 6.6L V8 Turbo Diesel
Allison 1000 6-Speed Automatic Transmission