Picasso, how do I get to the red door market?
Okay. I'm a total idiot when it comes to Itaewon. I've been there maybe six or seven times during my entire time in Korea. It's far as hell from my house, and I find the place pretty much intolerable after dark (except for the Hill, of course, but even that's something I can't handle all the time), so...
I might end up going there this weekend, however, because I have some business to attend to that cannot be avoided. In the case that I do, I will retrace the route to the red door market and make notes so that I can give accurate directions (people seem to be incapable of doing this at all in this case). I don't remember the exit number, but I know at least one of my "readers" aka friends lives in Itaewon and can probably respond with info to fill in the gaps. Basically you'll want to come out on the side of the street opposite the Hamilton Hotel (which you can't miss). Put the Hamilton to your back and walk up the street with Gecko's on the corner, away from the main street that the Hamilton is on. It will be not very far up on the left. It's not a red door... there's a red door you'll hit before you get to it, but that's not it. It's actually a door outlined in red. It's extremely tiny -- you'll think you don't have the right place, but you do.
I've been to the red door market once, after I first arrived. It took me about seventeen years of crawling through a deluge to find it. It definitely wasn't worth it. Things are super duper over priced and not that exciting, in my opinion. You'd be better of hitting the foreign food section in your local Mart and making due, in my opinion.
In conclusion, I hate Itaewon and good luck.