The big question is how deep is the frost line. I do eventually blow and plug pipes but as Winter approaches I try and keep the equipment functional as late as possible since I don't cover. Even with nights in the teens I just drain the above ground pipes and wrap a bunch of old rags around the multiport valve and filter top so the heat from the sand filter keeps the valve and gauge above freezing. The chlorinator has enough water in it so it won't freeze solid overnight. Have the added advantage of the equipment being located in a poolhouse that buffers the temperature swings somewhat. Of course the solar things are drained long before the equipment hibernates. Solar heaters are also good heat radiators and will freeze solid in minutes on a clear cool night.
Al