We will be home exchanging to Madrid in late September. For various reasons, we will need to be out of the Madrid house for a couple of days so we are considering a 2+ day trip to either Zaragoza or Salamanca. We've been to Spain before, even lived in Barcelona for a year in the early '80's, but never visited these two cities. Which is a better bet for just a few days? We like museums, strolling streets, hanging at cafes, etc.