Well I Gotta agree that going South Is the Ultimate Best Foolproof way to Winterize!!
For me, as I live here in The Great White North where we do get Temps to the -20F and cooler with the wind chill, I blow out all I can with the air, However I do not think this method gets ALL the water, I then fill it up with the Pink and then Blow it ALL out again, That way no taste or smell in water lines in the Spring.,
I do not think Just the Air will succesfully do the Washer/ Dryer, Maybe the water lines but not the Pump.
I have used this Method For many years on my Boats and the Last 3 on the Coach and had no problems.
'05 Kountry Star 3910 ISC 330 Cummins '08 Jeep Wrangler Four Door Blue Ox