Martinsburg WV...west of DC
The Metro option:
You can drive in 9 to 7 to 267 (Greeway, Dulles Toll Road) to 66, then exit to the East Falls Church Metro station. Usually on a Friday afternoon there are spaces available. Take the Metro to L'Enfant Plaza, where you switch to the Green line and go two more stops to Navy Yard station, which is a mere 1 minute walk to the entrance of Nats Park. You emerge, and there she is, shining like an opal.
I suggest Metro, because driving in to DC on a Friday gets you bound up in the incoming party/dinner crowd, and traffic can get bogged down. Inbound 66, and the 395 to SE / SW Freeway gets heavy, though not unbearable.