Mix glaze ingredients (bourbon, honey, mustard, tarragon) in a bowl; stir well and set aside. Steam or boil sweet potatoes until crisp-tender. Thread 3 sweet potato cubes, 3 pork cubes, 2 peach quarters, 4 green pepper pieces and 4 onion pieces alternately onto each of eight 10-inch skewers. Brush kabobs with glaze mixture. Lightly oil grill. Grill over medium-hot coals 5 minutes on each side or until thoroughly heated, basting occasionally with glaze.