Just got back from Fingerprinting...
For those of you like me, who sheepishly didn't pay attention to the address, the ASC (application support center) for fingerprinting is not at the regular CIS office at the Fallon Federal Building; it's across the street in the Bank of America Building -- where you take the escalators to the second floor. I spent about half an hour in the CIS office in the Fallon Building before someone spotted that I was in the wrong place.
The folks at the ACS are pretty clueless about N-400 procedures other than fingerprinting. When I asked, they even denied that there was such a thing as a "name check". They said the N-400 only had a fingerprint check, which we all clearly know is not true. They also said that regular naturalization interviews are conducted at the CIS office in the Fallon Building (across the street) and not at the location where fingerprints were taken.
Parking is abundant, especially if you get a morning interview/appt on a weekday. I commute daily to Baltimore city (have been doing so for the last 10 yrs so I know the city like the back of my hand), and there are plenty of parking meters on the 100-200 block on S. Charles.
Another option for those of you who don't want to pay extra for parking might be to park your car further down on Charles, or on one of the cross streets further downtown and take the metro to Charles.