My previous reply mentioned going to Foggy Bottom Metro station. The official GOE website is now calling for folks to go to the Farragut West station, in order to avoid encountering large groups of our opponents at the FB station. (I believe their charter buses are also unloading in that area, 23rd and Constitution so this other station will help reduce the chances of confrontation before we're united.) Be prepared to see/meet them in the metro trains and on the street, though.
Thanks for the info.