Ditto on needing to know the load for the gas. Without knowing, everyone is just guessing.
As to the water, x2 on the black Polyethylene (PE) water pipe. Thats what is used for wells AND even rural "city" water. It comes in rolls and I think is going to be cheaper than other options. But watch which one you get. SDR-7 is what our water company reccomends because with it, you can use compression union fittings. Not sure about the other types.