Actually, Zorro, if you look at the following two threads, from the True Story folder, you'll see that the Serum Run did run from Nenana to Nome (even in the cartoon, you can see a sign for Nenana next to the parked train, in the scene where the team picks up the serum):
http://baltosource.timduru.org/board/viewtopic.php?t=8889 (observe my post with the list of mushers...down a few from the first post)
http://baltosource.timduru.org/board/viewtopic.php?t=8919 (observe Coaster's post, with the trail map)
It is a commonly-held misconception that the team ran from Anchorage. That is because of the Iditarod. That race, which first ran in 1973, starts in Anchorage, and is meant to honor the participants of the Serum Run, and the Serum Run itself. Though it doesn't follow the same path. It follows the old Iditarod Trail.