I don't know of any specific tracks in those areas, though if you use google earth or an application that does (map my run is a great one) you can look for tracks... generally they show up pretty well on the application, though I've sometimes had a hard time finding them in real life (Seoul National University of Education took me a couple of confused runs to find).
There is an awesome track just across the Banpo bridge and near Sorae or French village. Not close close but not a million miles away. It is just west of the Express bus terminal along a bike path and in front of a school....
Is that the one that's 270m? Right beside the huge fancy looking apartment buildings that just went up? Or do you mean Banpo Stadium which is close to 400m, but is really for roller bladers (with the big dirt soccer field and the tennis bubble, etc.). Those two would both be a bit of a trek from Itaewon, but probably not far from Express Bus Station (line 3/7/9) or Donjak (Line 4/9) or the two new line 9 stops in between them. Both are fairly easy to find if you can get to the green rubberized path that (used to) run completely between those two stations (now there is a break in between for some construction, but some of the signs say that will be done by late June maybe).