OK, I have a physical copy of Red Hand of Doom, and I could have sworn that it included a map for the Streets of Blood encounter. Specifically, what I remember is this: One side was split into two halves, one of which had the Fane of Tiamat, and the other of which had the Marauder Attack from the very beginning. The other side was entirely Streets-of-Bloody.

I'll check it out when I get home, but I recall the road being at least 30 feet wide - this is the Dawn Way, after all.