An outdoor marathon can have legally allowed assistance characteristics. For example, a loop, probably by a lake, where one direction has it pushing at your back, then it returns through a downtown route where the buildings block the wind.
Also, you are allowed a drop of 1 part per 1000, or 42 meters for the marathon, from start to finish.
The finishing mile having a 2% decline should help the kick.
A better setup would involve a flat 26.2mi straight road. Anywhere in Indiana or Kansas would do.
finish needs to be within 21km of the start line via a hypothetical straight line. thus a one way course in Kansas with a tailwind is not eligible for IAAF record purposes.
stats guru ken young (founder of arrs.net) set the world bests for indoor marathons. ask him.
Quote from the article linked in the OP:
The music and commentating kept us entertained. We were like metronomes out there (except for when AC/DC’s Thunderstruck came on and I got a little excited!†– Calum Neff
This is key. In order to run a sub 2-hour marathon, we must have AC/DC's Thunderstruck on repeat along the race course.
I thought that the start line and finish line could not be more than 30% of the race distance apart, as measured in a straight line. 12.6k for a marathon.
If they are farther apart than that then weather readings are required to prove no wind aid.
download it and go to page 275
"(b) the start and finish points of a course, measured along a theoretical straight line between them, shall not be further apart than 50% of the race distance.
(c) the overall decrease in elevation between the start and finish shall not exceed 1:1000, i.e. 1m per km (0.1%)."
It used to be 30% - as determined by ARRS statistician, and running pioneer Ken Young (see link) - but the IAAF revised their rule to 50% I believe back when the IAAF pres. was Japanese and revising the rule would get his country a new WR (perhaps the womens road 100K but I cannot recall off hand).