Probably not RR ties, it will be shot up, but something visual to discern a line of sight like a chalk line does.
It would have to be raised high enough for shooters at the firing line to see. Some sort of squaring off the range lines and markers.
Like an orange plastic type snow fence stretched out the length.
Can we plant some sort of plants in a line or hedge, something needing little water as it looks fairly dry there.
Visual cues are needed for sure.
Maybe a Drone, we could take turns on Drone watch or have it connected to an Internet URL we could look at anytime.
Aw there goes the privacy, that won't work.