Most campgrounds or RV parks will provide dump access upon your departure. If you need to dump on the go, you can identify many gas station facilities such as Pilot or Love's that offer dumping stations.  Most smartphones can download the Park Advisor app that identifies appropriate dumping stations along your route. Gas stations can also offer water and propane, simply look up 'propane refill near me', and you can try U-Hauls as they usually have the cheapest and convenient services.