Punta Loma is the easiest wildlife trip from Puerto Madryn: a short drive south to low cliffs where South American sea lions haul out on the rocks below. You watch from above rather than walking among the animals, which is better for them and still close enough for good views.
Come with binoculars if you have them. The reserve is also good for cormorants and coastal scenery, and the gravel road out from town gives a quick taste of the dry Patagonian steppe without committing to a full Peninsula Valdes day.