In Canada without inside storage , you must go the extra mile. To each his own but this is what I do.
1-Drain hot water heater , position bypass valve.
2-Drain grey,black,fresh water tanks, pull 1/4" hose off ice maker valve and drain. close big "T" valve on fresh water drain so mice do not get in.
3- Drain blue and red low water line drains
4- Put the air to her cracking one valve at a time until misting subsides and you get pure air........or very close to it.
5- Pour RV AF in sinks shower and toilet ,flush toilet and then add more AF
6- Use about a five foot piece of hose , one end in gallon of AF and turn on pump, crack taps , sinks , shower one at a time till the pink AF is coming out. Remember to crack taps on outside shower also.
Your low spots and pump are now safe as the air and AF has removed/displaced the water.
I also remove the four house Batt's and the two coach batts and they go in my heated garage and are hooked to battery tenders.
Hopefully in a year or two my winterizing will be a tank of diesel with her pointed South. Cheers.