Good find!
So if we hypothetically say SB was alone and alive at 6:05pm (about 4 hours into her hike) and she seemed "OK" to another hiker, who she told she wanted to see a sunset (on a cloudy evening), and who believes she was heading "down", presumably back to the trailhead, IMO she either fell of a cliff after 6:05pm or she encountered someone nefarious at the trailhead before she could leave.
Given this hypothetical example also includes data that SB was comfortable standing on a cliff edge, the odds are, sadly, she fell off a cliff after 6:05pm.
IMO and Hypothetical.