Place potatoes in slow cooker. Mix sauerkraut, apple and chopped onions in large bowl; spoon half over potatoes.
Top with pork, kielbasa and remaining sauerkraut mixture. Mix apple juice, brown sugar and remaining seasonings in small bowl. Lightly stir mixture into sauerkraut. Cover.
Cook 8 hours on LOW or 4 hours on HIGH until meat and vegetables are tender.