UncleJay A couple of clarifications concerning your post since some people reading it who haven't discovered the Hard Part might be further confused.
1) The link you gave is to a post in the Old Forum. It is archived here because it does have some useful information at times, but it is mainly as a courtesy to those players who contributed information to it. It was never maintained and is in a state of disarray. This is one reason why I cannot easily find the specific mentioning you write of in that link, although it is probably there somewhere if I went searching for it for awhile. So providing this link does little good in this case for that reason. Better you provided a link to the exact entry speaking of what you are mentioning.
2) At the top of the screen of the floor you are on when entering Phantom's Alpine Castle there are two ladders, one in each of the rooms on either side of the hallway. Either of those ladders will take you to a floor where there is a ladder in the lower right area, which takes you to the Hard Area.