How to keep water lines from freezing

We share a vacation trailer on a lake in Northern Idaho. Water is pumped from the lake. Every fall we have to shut off the pump and drain all the water lines so that they don't freeze in the winter. To hook everything back up and get the pumping working again takes at least 5hrs and this is not practical for weekend get aways in the winter. We would like to be able to use the place in late fall and winter but not having water for toilets, showers, dishes, is a real drag.

I am looking for cost effective suggestions on how to design a water system that would be easy to turn back on in the winter and easy to drain when we leave. I have thought about switching to a submersible pump (it would be sitting in about 40' of water) but am not sure where to turn for advice.

Any thoughts or suggestions would be greatly appreciated!

A shallow well with a pump in a pit below the frost line would leave you only having to open a valve and possibly blow a little air from a small compressor to clear the lines to and in the trailer when shutting down for the winter, and to later turn the supply back on, just close the drain valve (and possibly prime the pump) and flip the pump's power switch back on. I lived in a mobile home many years ago, and that is the system we had there.

A submersible with all the lines pitched back to a drain below the frost line would be the ideal way to go.

drain

Drain petcocks at each low point would drain it quickly and also allow rapid restoration of the water flow.