Airport may be defunct, manager no longer lives here according to Whitepages

This is almost certainly part of the Rountree Trail extension to Belmont, but how does it connect?

Manager is deceased:
http://ssdmf.info/by_number/pages/111078.html

Manager is deceased:
http://www.ancientfaces.com/person/j-g-langeberg/54668513

There's probably a bridge here, but which road is the overpass?

MN 36 ends here, not at the state line

"Mitsubishi Motorway" sounds spurious, can anyone confirm on the ground?

I could not find any independent evidence that Laftheim Landing Strip exists.
Ashenfelter Aerodrome also does not exist any more, since its FAA identifier has been reassigned and its airport manager died in 2012.

Reconstruction of CTH D through mid-August 2017