Stay at the Oasis Madrid Albufera - great place just on the outskirts of Madrid for half the price. Only about a half an hour with the metro, so it's worth it. Vallecas itself isn't too great. The town center, however, is not bad. It's just when you come out of the metro station to your right. Go for some lunch or dinner at the Cafe just across the road - vis-a-vis the church.