I'm going to start a design log for the various parts of Rappan Athuk that I'm involved with. In terms of the old-school, Swords & Wizardry and 1e side of it, that will include pretty much everything about the entire dungeon -- lots of the input will be coming from Bill Webb, since he originally wrote the dungeon using first edition Advanced D&D, but in terms of structuring it as a whole, integrating the old work with the new, I'll probably be the lead person at that level. This leaves Bill to be free to edit the completed product with clear eyes, which is critically important. It's not generally a good idea to be both the designer and the editor, so although it's not a super-formalized division of labor, I think that's how it's going to pan out, for the most part. Bill created lots of original pieces, I will integrate those from the perspective of the S&W/1e rules, and then Bill will edit the results.
I'm doing two main tasks that are linked to each other. The first of these is simply writing several new levels (9-10). As a matter of keeping the feel of Rappan Athuk, it makes sense to retain the dungeon's original method of writing for the original rules, and then for the newer edition version, adapting the original-rules feel into the parameters of the newer system. All of the underlying design of Rappan Athuk has been done using 1e rules and design principles, and having parts of it that are designed using newer rule sets could conceivably create some areas that simply don't feel like Rappan Athuk. That isn't to say that for the Pathfinder version the dungeon won't be designed to work with the Pathfinder rules and design principles, but it means that, like the old 3e versions of Rappan Athuk, there will be the underlying dynamics of a true old-school dungeon.
For this initial design note -- and I don't know how often or how regularly I will have the time to dash these out -- I'll focus on one quick issue that has already been raised on one or two old-school message boards, and that is, essentially, square footage.
There is a radically different level progression speed in Original/First Edition D&D than there is in the post-2000 versions of the game. In order to create a megadungeon in which the characters can assault the lower levels, they need to have the potential to gain levels that will let them do so. As it stands right now, the upper levels of Rappan Athuk don't contain enough monsters or treasure (once treasure is scaled to the older systems) to allow that advancement.
Therefore, my focus is on the uppermost 8 levels of the dungeon, which is really (approximately) only 4-6 normal "dungeon levels" as meant in the 0e/1e sense of how difficult a particular depth is, and these correspond to roughly dungeons levels 3 up to about 8, depending on which part you're looking at. I'll write more about the structure of Rappan Athuk's levels, interconnections, and varying difficulties in later notes, but for now my point is simply that I'm focusing on the upper levels in order to provide enough stuff for level advancement to work properly in the megadungeon sense.
The Pathfinder converters are already dealing with the converse issue, which is that apparently a party could accumulate enough xp to become too high level for the lower areas of the dungeon. I don't know how they're going to work with that, but my job is to make it work for old-school rules, and this is the first job -- more square footage in the uppermost levels.
That's enough for now, since ... I actually have to go work on this relatively herculean task rather than blabbering about how I'm going to do it. Probably I will have another post about the overall structure of Rappan Athuk's "cross-section" map fairly soon. So if you're interested, click to follow the blog. I might also from time to time grab some comments or design notes from some of the other folks who are involved in the process.
Final note -- the Tome of Adventure Design is out for preorders, should be delivered before Christmas, and the pdf is delivered immediately when you order it. Since it has some of my general thoughts on old school megadungeon design in it, if this topic is interesting to you, it also gives something of a window onto what's going on behind the scenes of the Rappan Athuk project. And if you're an inveterate dungeon designer yourself, I think it's a great resource -- it's what I use whenever I draw a creative blank.
Stay tuned -- same bat channel and all that!
First Design Note
Second Design Note
Third Design Note