Recently a lot of progress has been made with the ability to mod the DOS version of TES Arena, including the ability to straight up create new custom levels. However, we are still unable to add new locations to the world map, but we're very close.
From an already known formula (which is explained here https://github.com/afritz1/OpenTESArena ... Generation), Main Quest dungeons in Arena use their XY positioning and the province they are in to determine the name of the mif file (Arena's level files are mif files) it will try to load. Recently I discovered that random provincial dungeons will also generate the name of a mif file too, they just don't attempt to load it. This discovery was made by making the name of a dungeon one byte longer than its maximum length, as shown here:
If the small piece of code in the Arena exe that stops provincial dungeons from looking for this mif file could be changed so that they do look for the mif file, it would unleash the floodgates of adding new locations to the world map and adding proper custom dungeons without replacing old dungeons. Any help with this would be greatly appreciated.