[mqslkzeb] Possible Steiner points

Drawing Steiner trees on maps of the real world runs into the problem of selecting cities.

Compute Steiner trees (perhaps approximate) for many possible subsets of points, generally never omitting larger cities in favor of nearby smaller ones.  What Steiner points appear frequently?

The fascinating aspect of Steiner trees are these "extra" Steiner points that appear out of "nowhere", so, in the real world, a critical junction between important cities may very well be in the middle of nowhere.  Perhaps adventures for geocachers.