It probably wouldnt hurt to to actually take your battery out and put it in your home while you are gone, if it is going to be getting really, really cold. As far as fluids go, make sure to have a newish oil change, if not may want to do so and have your antifreeze tested. If your really going to be paranoid about your water freezing I guess you can always drain the system, but it in 2-3 gallon jugs, and keep them in the house with the battery. Main thing of it it all though if it were my car would to make sure I didnt have a thick weight oil in the car, something around 5w30, and to make sure my radiator had a 40/50 mix, NEVER fill with straight antifreeze for it is flammable in higher doses over 80%. You can also buy a engine block heater that you can plug into your ac outlet if you have one outside too. But what ever you do make sure to get at least your antifreeze tested, if that freezes the expanding water will crack your head or block, and that will cost a lot to fix.
Also DO not waste your money of premix 50/50, thats a waste of your money and should buy full strength in the bottle.