Winterizing water line between tank and pump

[Packed2Go]

I've read the winterizing section of the user manual that came with my 321RES,
I've seen countless videos and forum discussions but none address winterizing the supply water line between the pump and tank. They do mention emptying the tank and then running the pump until it draws air but I would still think water drops could run back down the line and freeze. The discussions mentioning putting RV antifreeze in the tank seem to have a mixed following. If I was to run the pump until it drew air and the residual water drops simply drained back into the tank, then I'm fine with that but I assumed that there is a check valve in the tank - end of the line to keep the water from draining back into the tank.

Comments please.....

Thanks in advance,
Pached2Go