Those signs aren't understood by everyone, so here's what you could do.
Go down to the local gravel pit, stack about fifteen paper targets on top of each other and unload a clip or two downrange into these targets.
Next, go back to the property and place these at the edge of the properties perimeter, every forty feet or so, with the target side facing in, towards your cabin.
Now, from any approach, any fool should see he is at the wrong end of a target range, and may just turn back onto the trail, and boogy.
Now there's a universal language, understood by all.
