After reconstructing everything with geometry I decided to cut down the environment a bit from 3 segments into 2. It's less overhwelming in terms of ammount of work and more managable to fill with detail. I made everything modular in my max file so that expanding it when everything is textured and unwrapped will be a matter of just copying the geometry and updating the .cgf (mesh) files.
Here is a bit of progress so far. At the moment modeling all the metal supporting structures with all the pipes and detail that will go on the "outer shell" of the environment. Still got to decide if to import it as one big mesh with 15 submaterials to it and dress it all with meshes or to just export the individual modular bits and build it inside the engine. Might even find a compromise between those two. But that will be decided once I'm done with modeling it. I plan to finish and texture the base architecture by the end of this month so that the next month will be down to filling it up with assets.