Driving to DC
There's a discussion on this earlier on the thread which you should check out, but I would say in Baltimore you should go to Faidley's (they would have crabcakes, shellfish - though probably not lobster) at the Lexington Market and make sure kid saves enough room to go enjoy 1 or 2 Berger's cookies (at the Berger Bakery stand) inside the market. Even if the kid doesn't like the offerings at Faidley's there's a ton of other types of food there, including old standbys like fried chicken etc. Plus it's very busy exciting. (one warning, you should be aware that this is a very urban environment and you should take some time to not look too touristy. I used to go there pretty frequently though and never had any trouble.)
re: jen kalb
We used a lot of the suggestions and enjoyed some great meals. We never felt unsafe at all in the Lexington Market in Baltimore and my husband had "the best crab cakes ever" at Faidley's. Another note in Baltimore pretty good food for a chain and good beer and very kid friendly is The Capitol City Brewing Co. at the Harbor.
In D.C. we had great chinese food at Full Kee on H street in Chinatown.
A great brunch in Alexandria on Sunday was at the Virginia Brewing Co. Huge waffles with many choices of toppings - Cajun Fresh Roasted Turkey, Roast Beef , Pastrami, omlete station with flames shooting sky high (fun for kids) plus other offerings - really didn't like the chese grits.
Coming back to NY we stopped in Havre de Grace and had a terrific lunch at the Tidewater Grill - not on a main street so we had to ask to find it. Very nice icecream shop down the street (don't remember the name but it's the only one).
Glad you had a good time. I actually would not have thought of Virginia Beverage Co for breakfast. I'll have to check them out. Also wouldn't have thought of
Capitol Brewing in the Inner Harbor. I'm not huge on their beers down here, but actually they're the closest microbrew to me. I should remember to put them on my list.