New World Old Skool!

Since I've been trying to preserve my old 1st edition AD&D books by typing them into the computer, I've been getting the itch to create again. I know I have limited time and all but I actually miss creating new and unique campaign elements. The closest I came to an original setting was Thuin, but later decided to scrap it since the interest wasn't there anymore. I'm starting to get more of a Sword & Sorcery vibe from 1st edition so I might like to try my hand at making a mega-dungeon and little details about the surroundings to begin with. This worked well with Thuin in the beginning, but the characters developed more of a wilderness bent in later years. What I may want to do is more of a Castle Greyhawk setting where the dungeon is the main antagonist and the players simply exist to explore its depths and find the treasures and mysteries. Using only the AD&D books originally published to make the game seems to be the way to go - no Unearthed Arcana or Survival Guides necessary. All by-the-book rules (those that aren't broken) to run the combats and spells involved.

I was going to revamp Thuin but decided that the dungeon as written was too campaign specific and needed to be redone anyway. A fresh start may do me good.