Tried it, it is a good route. You did a good job at documenting chests, but there are at least 5 Relic Iron spawn points in that area: one near the yard before the round building, one immediately at the entrance of the round building (the one you noticed later in the video), one inside the round building, just below where the enemies spawn in the middle, one to the side of the round building, one between doors to 1st and 2nd levels (they have separate entrances), and one a bit further where the road turns right - you go straight and it is just behind a small dune. Thanks for the video, just running around doing patrols will get you them eventually, but this is much more effective.