On the question of how hard it is to get tickets ... I was on the T one evening a couple of years ago on a Friday night in June, during interleague, when the Cardinals were in town to play the Red Sox. It was about 6pm. The entire subway system was infested with Cardinal fans. (You can spot them, because they all dress up, either as Albert Pujols or Stan Musial.) Presumably they all had tickets, so there must be a way to get them. And the Nationals are not going to be a big draw, compared with the Cardinals.
A couple months ago I was in Chicago getting on an airplane and there was TONS of Cubs fans going to Boston for Cubs@Fenway
