Depends... what do you mean by freeze proof??
Normal practice is to assume the house is always heated and then keep the pipes mostly where it is warm, heavily insulate where the pipes must run close to a cold outside wall, bury outside lines below, frost line. apply electric heat tape in a few critical areas if necessary. pipe material is not really a problem except you shouldn't use heat tape on plastic pipes. copper, galvanized iron,cpvc, or PEX should work fine.

If by freeze proof you mean can withstand an ocassional total freeze up without damage. Then you better talk to somebody about a secound mortgage. most conventional hardware store pipe fittings and valves will not stand up to this. You'll need heavy wall stainless tubing and fittings, high pressure valves etc, and there is no way to freeze proof the connection to conventional plumbing fixtures, so you'll end up with a real funky looking kitchen sink and shower!! I saw some pictures of what looked like this type of plumbing in amilitary outpost of some kind that was ocupied intermitantly. It was just in the background so i couldn't see much detail.