[ChuckS]

I prefer to use low pressure air to blow out water system first. This is done after draining water heater and low point drains ...

A RV air hose adapter is available at just about any place selling RV stuff. Wally World carries it as well

Make sure to also blow out outside shower drains and washer line.

I then pump RV anti freeze thru all fixtures and toilet.

And don’t forget to blow out the black tank flush as water will sit in the line and anti siphon valve and crack if it freezes.