You want to keep that switch as close to that tank as possible so it isn't subject to any eratic pressure variations. I would suggest keeping it at the tank. It sounds to me like you have a 6" well. That water line should exit the casing atleast 4' below grade so it doesn't freeze. If its on a well seal, I would suggest you have a well company come out and re route that line below grade and have a pitless adapter installed. That way the pipe will not be exposed to the open elements. Do you know how deep that water line goes into the ground and is that the only spot where it freezes? If it is the only spot then i would have a well company install that pitless adapter to hower deep the line is.The pitless adapter is a sealed fitting that connects the submersible drop pipe or jet pump drop pipe to the waterline.When there is a problem with the pump,footvalve,or jet assembly,it disconnects on the inside of the casing for service. GET THAT SECTION OF WATER LINE IN THE GROUND.