Water in pipes close to the surface can freeze pretty fast. I assume that is the concern raised in the initial question. You rely on circulating water to keep pipes from freezing. Only two options you have are already stated. Generator or Winterizing beforehand. My option would be the latter. If you have to rely on a generator to prevent pipe freezing, Murphy's Law will kick in....If something can go wrong...it will. Won't start, long outage, out of gas...etc. All you need is one short ice plug in a pipe to stop circulation and you're screwed. Winterizing to drain and plug pipes doesn't take that long once you get the hang of it. Then you can relax and enjoy the ice.
Al