Cerro Viejo is less a single packaged attraction than the mountain presence that defines General Zaragoza. It rises close enough to be visible from much of town and helps explain why this corner of Nuevo León feels cooler and greener than the plains to the north.
Ask locally before setting out on trails or mountain-bike routes. Conditions, access, and weather matter here, and this is the kind of place where up-to-date local advice is more useful than a fixed itinerary.