Not how it works.TCP/IP map is temporary, that's right. But if you host a TCP/IP game, then you delete your original map. So when you start up a normal singel player game again, a new map is generated. Like this:
map "A" ?
map "A" ?-normal games
map "A" ?
map "B" <- your TCP/IP game
map "C" ?
map "C" ?-normal games
map "C" ?
map "D" <- your TCP/IP game
map "E" ?
map "E" ?-normal games
map "E" ?
Will you generate a new map for EVERY map in the game or just the ones you enter in the TCP/IP game?
The .d2s file is the most important one. Like you said, it's what GoMule accesses. The .key seems to be a registration entry. I don't know a lot when it comes to registry related issues, so I can't help you there. The ma0 etc extensions are related to your maps, sorted by difficulty, not by act. If you reroll your map (or misclick a difficulty), you get a new one, so that's why you have 4, and there are only 3 difficulties. And I don't know what the .map one does.Okay, I have a related question.
Here are the files I see in the "Save" subfolder of my Diablo II folder:
Noob.d2s
Noob.key
Noob.ma0
Noob.ma1
Noob.ma2
Noob.ma3
Noob.map
I deduced that the .d2s file is my character, as that's the one that GoMule accesses whenever I transfer gear. But what's the .key file for? What's the difference between .ma0, .ma1, .ma2, .ma3, and .map? Are they the maps for the five different Acts? Or are they something else?