I don't think this would be more complicated then the map generator itself. It is just that the map generator on its own took years to where it is now.
In fact, in combination with the navigational mesh you likely have everything you need if you add in some prefabs for a base or two. Or try and generate that too, as Balthazar did with his city generator. I think what you describe is technically possible, maybe as simple as a (large) mod. The only issue is time 🙂