Good question. We are lucky enough to go somewhere warm in winter but did the winterization for many years. We replaced RV fridge with a residential model this summer and I wondered the same thing.
The procedure for the Norcold RV fridge ice maker was to shut off the water and run one cycle of cubes. Never seemed like good enough for me but did work.
If you fill the lines with RV antifreeze I suppose you could run it through the dispenser but I'm not sure how you would handle the ice maker.
Mark & Nancy
2004 Winnebago Vectra 40KD
Shep dog, R.I.P. Kenzie dog Toad 2015 Jeep Wrangler Willys Wheeler