While remaking the arena, we didn't have any plans of surronunding buildings, so we looked at screenshots and placed closest ones so they would look a bit like the original game, and further ones at random.
After some time we recieved and extracted original game files, so we could map exactly where each building was:
We weren't able to copy anything from there, just view and take screenshots, so we copied the layout into... Excel:
We used this spreadsheet to place all the buildings in the 3D environment and to create ground texture:
You can see how it looks now here:
We also fixed the hole in the wall surrounding whole arena that was too small- thanks to jork for the tip ;)