The entire sequence was just over 2900 frames. About 820 of those were clear enough and stable enough to be useful. He appeared to shoot from three locations - (1) close to the main fuselage first impact site in the trees, about 300 feet west of the tracks, (2) just east and below the tracks and virtually under the high tension line, and (3) on a hill east of the tracks, elevated above them and slightly southwest of position #2. Since he was panning I should be able to map his location pretty closely.
The scaffolding looks like a permanent installation, not a temporary structure. It appears to have concrete footings. It doesn't seem to have any equipment. It's possible the platform on top supports lights that aren't obvious from this angle.
Three panoramas made from these sequences might be instructive.