I will be spending two full days sightseeing around Stockholm before traveling to the Skinnskatteberg area for a tour. My tour there will end late morning on a Sunday and I fly out of Arlanda airport on Monday morning. Instead of returning to the center of Stockholm on that Sunday, I was considering going to Uppsala since I've heard it mentioned as a good side trip and it is also relatively close to the airport. Would Uppsala be a good destination for a half-day? Is it easy enough to get to and worth seeing? I am also open to any other suggestions on what to do with this remaining half day.