I have a work trip taking me to DC in a few weeks. I've done DC several times, so I plan to take a couple personal days and travel to Baltimore and Philadelphia. I've never been to either, so give me some advice on what to do. I'm staying the Inner Harbor area of Baltimore (Royal Sonesta) and near Independence Hall (Kimpton Hotel Monaco) in Philly. I will be checking out a Phillies game but the orioles will not be in town while I'm there.