Although I agree that the Metro is probably not the best choice, the Blue Line is not the way to do it as it has more stops. Take the Red line from Metro Center (2 blocks from the National Press Club, actually closer than Federal Triangle) one stop to Gallery Place. Transfer to the Yellow line to Virginia. 7 stops total (including change), while Blue line is 10 stops from Fed Triangle to DCA.

The Blue line route is a mess, due to the new Silver Line trains having to share the Potomac river tunnel with both Blue and Orange between Foggy Bottom and Rosslyn.