Is it possible to hide the roads and paths with just the addition of grass meshes? I think I may have another idea. How about doing a static mesh (like a rock) shaped the same way as the landscape, elevate it slightly above the actual landscape and texture it with grass, then disable it by script as the quest progresses. Then it will reveal the true landscape mesh underneath which has the final paved texture. I'm not sure if the LOD might have quirks though, but do you think that might work? You could do it in stages. I think you can get away without adding collision to the fake grass mesh, too.