Oh, that's a good one! And, you can get up there on the cheap. $7 each way on the MARC Camden Line out of Union Station. Takes you right to Camden Yards and you're just a block or two away from the Inner Harbor.
Mount Vernon is also a good day trip. The girls would probably enjoy that. There's also Williamsburg, but your kids may be too young to enjoy most of that: the historical stuff they haven't really learned much about yet, and they probably won't be able to ride most of the rides. Probably better to save that one for another trip, but you know your kids and I don't.
Ummmm....
Slight incongruity there. :p :D








