Put the peanut butter chips in a microwave-safe bowl and heat in 30-second intervals, stirring in between each, until melted. Roughly chop the trail mix into smaller pieces and put in a shallow dish. Dip each caramel apple in the melted peanut butter chips, then roll in the trail mix. Let stand on parchment paper until set. If you like, place the dipped apples in a windowed kraft paper candy-apple box and tie jute twine on the stick.