We still have not yet built a road on the hill due west of Yun Quiling. I consider this critical for the defense of that town as GCA will likely attempt to dislodge us from there.
Our current road network in that region is nightmarish in terms of defense but can be corrected easily by building this new road. As it currently stands, Yun Quiling is 3 tiles away from Jiang Mapi - a convenient single turn of movement in case we needed to reinforce that town.
However, since the road crosses the river where it does, not only does it require 2 turns to reach Yun Quiling from Jiang Mapi, we have a vulnerable section of road that GCA could pillage, effectively disconnecting the entire nation from our iron. If we were to build a road on the west bank of the river, then we could defend that road better (GCA would have to attack a hill, across the river...).