The Material blends five groups of color, normal, and roughness maps using vertex RGB, Alpha, and 1 - Alpha. The blend transition is further assisted using a blend map and HeightLerp.
I'm pretty satisfied with the results. Now that this is complete putting multiple sections together should be a breeze.
Below you can see a result of the blending. All the materials and modeling, as usual, are completely original, running real time in unreal at steady 120fps.