In that case, you would likely be dealing with a great deal more information. There is another member of the guild, GamePrinter, who, I believe, is doing something similar, so he might be able to offer more information regarding the process. In the interim, however, my best suggestion would be to take a look at the various source/setting books that are available for some gaming systems. At a minimum, however, I would think that such a book would be geared towards Dungeon/Game Masters and would therefore require enough information and maps for them to run the game reasonably without too much fudging of the details. To that end, perhaps;

Regional Map
Sub-regional Maps
Local Maps
Area of Interest Maps

In addition, you'd probably want the following as well;

Regional Histories (perhaps in a time-line fashion with just a few notes)
Local Histories (again in a time-line fashion but a bit more detailed)
Important Local Figures (i.e. Mayors, Dukes, Kings, Past Heros, etc)
Some detail regarding politics and local relations
Some detail regarding religion
Some detail regarding non-human races/settlements (if they exist)
Some detail regarding random encounters (both hostile and non-hostile)
Current events

In a nutshell, my guess is that you'd want to provide as much "known" information as possible to potential DM/GMs while still leaving some room for individual development. On a personal level, when I look at a source/setting book, the things I look for are those that I've listed. For the most part, if I am going to buy a source/setting book, the reason I am doing so is to save time when it comes to those major details that I've listed above and concentrate on the actual play/adventure time.

GW