What about water?

Although cold water is straight forward, it becomes tricky if you want hot and cold.  It is much easier to install an under counter water heater rather than running hot water from the house.  Also make sure you have a shut off valve and an option to winterize/drain the system for when frost is a possibility.  As for waste (grey) water, the cheapest/quickest options are to have a removable container to catch the water from the sink but this is limited by the size of the container.  Another option is to include a connection to an existing drain or household sewage line.  As with the gas, it is best to have a qualified plumber to complete this work.