OK, finally got a hold of someone at the phone number. He said basically the same thing, that the Confirmation Letter is not essential. He said the most important thing is the passport. I still plan on bringing a print out of the main screen and the interview schedule screen. Even if they are not needed, better safe than sorry when I am driving 4hrs.

Also, I just got an appt. at Dulles on Sunday 6/5 so I am happy. I think any sooner than that for the next weekend would be unlikely, but I will still keep my eye out.