Watched some of Ross' run. Painfully complex terrain. At times I thought running on marsh edges was the key, say 2>3, 4>5, 5>6 but 6>7 seems a "mishmash" of technique choice. 'Don't get lost' being the main message.
The problem for me is distinguishing the marshes. They are so plentiful, along with the knobby hills, that I frequently come up short, unsure of which marsh is before me. Visibility is fairly good over about 50-100 meters, but as the area is basically flat, so it is hard to see how large a feature is from it's border.