Hi Indigo Rose
When the Trolls mentioned they were developing a set or rules that would be close to OAD&D, I just had to get involved. As you likely have heard, I've been considering doing a publishable version of my original Greyhawk Castle & Dungeons for some time. The C&S rules should be perfect for that project.
I am so confident of the matter that I have already begun, written most of a campaign-base setting module that's titled ZAGYG'S CASTLE, YGGSBURGH, Part One. It is very large, covers an area the size of a small state, has a walled town, smaller communities, wilderness areas, and a lot if information for the GM in addition to many adventure encounters and springboards for others. I have yet to complete five dungeon-like level areas that are part of the adventures detailed in the base work.
Meantime, Rob Kuntz if writing the second part, the DARK CHATEAU, a sort of introduction as to how Zagyg became as he is now.
After that Rob and I will go to work on the upper levels of the castle, then the dungeons beneath--likely six additional modules, alhtough it might take more to get in all the best of the old levels.
It is going to be a lot of work, but also a good deal of fun
Cheers,
Gary