Guys,
Your over thinking it. The winterizing hose does bypass the tank. But it does go into the supply system, providing pressure just like you were taking water out of your main tank. Just plug one of your outside hoses in, then stick it into the main tank fill opening. Then turn your pump on, and it will pump, out of your jug, into your standard coach plumbing, then out your hose, into the main freshwater tank.
TimK