Regarding the original question: I haven't seen anything that might have an influence on this in the ini file, so I guess it is hard-coded in the .exe.
Yes, the minimum distance between cities in Civ 3 is hardcoded and in the Antal1987 exe it was set to zero (allowing canals) by hexediting. I think the reason for the hardcoded minimum distance between cities of one tile was to prevent building cities by 'combat settlers' next to the enemy city containing barracks in those cities. As CCM holds government-specific barracks and the number of barracks is strictly limited for most governments in that mod, I decided to use the Antal1987 patch for this mod. The advantage of building a canal to cross an isthmus (see the screenshot above from one of the CCM2 testgames, building the 'Yokohama Channel' - canal would be better fitting) is too tempting.
So the minimum distance between cities is hardcoded, the game can be forced by special settings in the editor (setting the minimum distance between civs in the world size registry of the editor to a high number on a small map) to ignore hardcoded minimum distances of the editor when starting a game. I posted about this phenomenon in the thread '
Overcrowded Start'. Edited: I don´t clearly remember, if the civs founded the cities at their starting locations or wandered around to find places with 'one-tile-distances' to other cities, but I have 'the feeling' they founded the cities and soon battled each other - and what happens, if the map leaves no more place for the civs 'to wander around' ?
Right now all that site hosts is an online version of the Conquests Civilopedia. I threw it together so I could look up gameplay information without having to be in the game itself. I thought I might never actually use it, but it comes in surprisingly handy for quick fact-checks.
May be the possibility, to go during a game to an online 'Game Help' could be an interesting idea. When having a closer look at the screenshot about the 'Ingame Help' of CCM2, you can see, that the structure is limited, due to some limitations in writing civilopedia entries in Civ 3. Per example several 7a) and 7b) entries are needed to form a correct list of these entries, as otherwise the structure would be disrupted when contacting the 'Ingame Help' during the game.
Caro-Kann, how did you manage to place the cities next to each other in the editor ?