Not really any different than a house. A hot and a cold supply line, ending with standard hose thread and a shut-off valve, plus a 1.5" waste stand pipe with a P-trap at the bottom where it begins to travel horizontally to the gray tank. You also need a 120v/20A electrical supply and a standard dryer vent in the exterior wall nearby. The details will vary with your rig layout, of course.
If you plan to use a residential style stack set, you probably want to change the dryer over to 120v operation rather than 220v. 220v operation would be very restricting unless you always have 50A shore power and/or your RV generator is also capable of 220v/50A. Many are not, even though they do supply 50A power.
2004 American Tradition; 2014 Buick LaCRosse
Homebase in the Ocala Nat'l Forest near Ocala, FL