maybe it would help if u put up a temporary fence across where they enter the path at. not a wood big deal type fence but pound one those green stakes on either side of it & attach some of that wire fencing that comes rolled up to them to block them from using it as a path? it would serve as a "hint" you would rather not have ppl using your property as a path and after a while they wont do it anymore and you can take it down after that.. also id post a few "no tresspassing" signs around your yard too.