baelon is the nearest "big" town to Emond's FieldI'm not sure anymore what is in which books, so dunno. But I trust ya on this.
If they put too much stuff in people will be overwhelmed, or characters will not get enough time. Seeing as you have a lot of important characters right of the bat, it won't be easy to find the right balance.
so its the first "city" that they temporarily stop at on their journey. they later realize that baelon was just a town in comparison to the major cities out there