How to mod the Westerosi roads?

So I asked this a few times on the old site but never got a straight answer; hopefully this time someone can help me out. I'm trying to find just where the modifiers that control the Westerosi roads (Kingsroad,goldroad, ex ex) are located in the mod files as I'm wanting to expand parts of the Kingsroad to the Wall and add the roads into Essos to simulate the Valyrian roads. So if anyone knows where these files are please help!