Best to be well insured, with signs placed as needed, having the Sheriff's Dept. explain criminal tresspass to those found trespassing (be armed in an attempt to avoid a fight when you remove the ATV key to keep the trespasser there until the deputy arrives) place game cameras at strategic points, and prosecute repeat offenders. Some counties have "if you don't own it, stay off it" laws, but trespassers might still be able to recover damages if injured on your property by nail boards or other booby traps. And although many of us think about taking them out, who really wants to walk up to the body of a child or adult he had just shot?