Cerro Potosi is not hard to find but the dirt loop that goes Galeana, Rayones, west to Cienaga, Mimbres , Dieciocho de Marzo, Cerro Potosi, back to Dieciocho, back to Galeana is quite doable in a day.
The road up the mountain is rough but not technical, just bone jarring. View is worth it.
Gee. Digging all my maps out makes me want to go back and explore more of Nuevo Leon.