I have occasionally been on sites where it ends up the short cut, not because its a path, or roadway, but just laziness. so typically I will block the path, orientate my truck, the kids tent, the trailer, a clothes line my fire wood pile, the extra picnic table, or whatever else is available to tastefully without being to obvious or making my site look like a prison,, block the route,,,, and when that's not enough then I politely redirect them letting it be known I will not trample on their privacy if they respect mine. I have never had anyone who in one fashion or another could not be convinced to respect other people's space.
As for dogs, it comes once I understand it got off its leash, catch it and be done with it, no harm no foul, the next time, I typically call the park warden, and usually don't see the dog loose again after he/she pays a visit, I don't bring my animals to the park so I should not be forced to tolerate other people's animals jumping all over me or anyone else on my site, peeing on things as it wonders through marking its territory, had one tried grabbing at a sandwich my son was eating, knocked him down when he jumped up on him (was 7 at the time), all the owner could yell across from his site across the road is "not to worry he is friendly" the guy did not make no attempt to call his dog back, I had to yell at him to get his dog off my site.
no I am not a dog hater, but I do dislike the people that have no respect for others when it comes to their pets