This 1100-sq-km desert park is overlooked by the vast majority of visitors; if you visit you'll have its beaches and mountains largely to yourself (unless you're lucky enough to spy a tortoise or bird of prey). El Morro is the very manageable peak to climb. At 239m it can easily be tackled in a morning or afternoon by most visitors.
To get there, follow Av San Fernando north to the beach and continue to your right until the road dead-ends at the ranger station.