John is right....as long as you keep the heat running, you should be in good shape. The furnace in the Bambi has a duct to the grey tank below. The black tank is mostly above the floor and the fresh tank is above the floor as are most of the fresh water lines.
If it is going to be less than 32 degrees as you say, I would throw some of the pink stuff down the drain(s) and some in the black tank, just so that the exposed section of PVC that is outside (pre dump valves) has some antifreeze in it as a precaution, but that's just me...possibly a 1/4 gallon to each tank. Some may say overkill, but at $3 a gallon, not enviornmentally toxic and the cost to dig into it if something did happen (which I know may be rare), seems to me only slightly overkill.