Well, after you have got the Ulitmate key after defaeting Goreham-hogg, you'll be able to unlock those pesky iron doors. to get to the best shop in the game, go to dourbrige, and you know there's a kid in the water, next to the arch? walk through the arch so you'r standing in the middle, with your charcter facing the right. next, walk up against the wall of the arch and very slowly walk up. a '!' will appear on your hero's head.press 'a'. you will unloch the iron door and just go down the stair - the shop had some of the best equipment in the game - i only found it by accident on my way back from max meddlin.