To put this in terms of flying over North America, this would be a little like a flight originating someplace in Western Europe, bound for ATL, then being told ATL is closed, first trying to divert to JAX, getting about halfway to JAX and being told to turn around, and ending up at IAD or BWI (CTS appears to be a little over 500 miles north of NRT).

This issue of where to divert if you can't land at NRT came up on my December MR LAX-NRT, when there were surface wind gusts in excess of 50 knots at NRT, and we were in a 747-400.

We didn't fly the Arctic route, but rather crossed the Pacific on the 40th parallel (on the USA side, about 50 miles south of Eureka,CA; on the Japan side, at the north end of Honshu island), and then angled down to NRT, which is at 35 degrees 40 minutes N. It took 11 hours 26 minutes to make the crossing.

I wonder what would have happened if planes, like the DL flight in the OP that had overflown the Aleutians, had legitimate emergencies, couldn't land in Japan and had to land on the Kamchatka Peninsula or Sakhalin island (I'm guessing the Soviets built military airports with decent length runways)