Just one comment since you are creating new models.
When you are creating something big and flat like a wall or fence, make sure that their long sides are not just a couple of triangles to span tens of meters. This will cause very odd ground shadows as if the wall was curved or lifted above the ground.
Just split large surfaces into multiple triangles no bigger than 1-2 m.
To make ground shadows visible for 20 km around the player I had to add some math tricks and "bend" the coordinate space. And long straight lines don't fit well into this curved world
Also note that textures for facilities should be inside "buildings" folder. Otherwise the shaders will treat them as moving objects (like cars) and will only draw their shadows at close distance.