I do a two stage process:
1: After Dump a couple jugs of the cheap wino/frat rat vodka into the FW tank. Run it through all the lines until it comes out all faucets.
2: Attach compressed air hose, blow lines out. Any water remaining in the lines will be mixed with ethanol and the freezing point will be low enough to not have lines crack here in Texas.
A northern state, I wouldn't recommend this. However, the nice thing about doing this is that ethanol kills bacteria. I still sanitize the lines anyway, but this method means no foul taste after a rinse or two.