Okay I think I figured out what the two cairn things are.
They are marking the approach to (from Wynarka direction) a turn off/track that crosses the railway and goes toward the farm behind.
It's not so easy to see from ground level, which would be a good reason you would want a marker to know when to throw out the anchors.
A mates farm has a similarly hidden entrance, he has reflectors nailed to a tree for this exact purpose.
If you stop this video at the 12 second mark, you can see the cairn to the left and the turnoff/track to the right, with the tent protecting the crime scene smack dab in the middle. At the 32 second mark you get a clear view of the track and railway crossing.
https://youtu.be/E93f-rCXVH4
Edit: That is if they are not actually marking Angel
They are marking the approach to (from Wynarka direction) a turn off/track that crosses the railway and goes toward the farm behind.
It's not so easy to see from ground level, which would be a good reason you would want a marker to know when to throw out the anchors.
A mates farm has a similarly hidden entrance, he has reflectors nailed to a tree for this exact purpose.
If you stop this video at the 12 second mark, you can see the cairn to the left and the turnoff/track to the right, with the tent protecting the crime scene smack dab in the middle. At the 32 second mark you get a clear view of the track and railway crossing.
https://youtu.be/E93f-rCXVH4
Edit: That is if they are not actually marking Angel