A plateau in the mountains looks good, but again with a bit simpler base economy. And it would be harder to get out to the eastern plains, and connect stuff there.
Then there are the coastal cities with a bit of reach inland, near Shanghai, and at Hong Kong down in the south. Terrain isn't that simple.
I decided to lay the first pair of tracks between the rivers, connecting Huainan and Xuzhou, with middle sized stations to spare some moneyz. That cattle ranch was in the way, but it will come in handy - as we're gonna see - so I did not bulldoze it.