Ed is a gap-toothed brahmin dealer, who can be found day and night in a shanty shack near a pen of brahmin. When he was a lot younger, he used to drive brahmin through the Big Circle. It just got too dangerous after a while, so he settled in Vault City.
The Chosen One can be lead to Ed by asking Vic where he found the "Vic's Water Flask". When near the shack, Vic will say "This looks like Ed's place" or something of the nature. The Chosen One can ask him about the origins of the flask. Then he will give you locations of some towns, like Redding, New Reno or Broken Hills.