Sorry I didn't see this thread sooner. Anyway, for future reference.

The light rail runs 7am - 11pm on Saturdays and 11:00am - 7:00pm on Sundays.

Once at the Inner Harbor (short walk from camden Yards) buy a water taxi ticket and go to either Fell's Point or Canton. If you have never been to the Inner Harbor it is nice to walk around but you'll find better food and better prices in Canton or Fell's Point. Plus, they are really neat areas to walk around .... lots more atmosphere. You can also stop at the fort if you like that sort of thing.