I can confirm that getting from Reagan to the Smithsonian via Metro in that time frame is easily doable. As for the other, as I recall the end of the green line doesn't reach Columbia, and Baltimore is farther than that though I'm unsure as to the length of the drive. This means that we'll be trying to get from DC to Baltimore during the lunch rush hour. Hopefully there won't be as much traffic at that time as there is at the end of the day...

In light of this plan, I can now confirm that I will not be in costume for Saturday as that would require a second bag, and I refuse to lug a second bag around downtown DC for a couple hours when I can (and will) fit everything I otherwise need for the weekend into a backpack.