Soak wood chips in water 30 minutes. Drain well.
Remove and discard giblets and neck from turkey. Trim excess fat. Combine onion, apple, sage, 1/2 teaspoon salt, and 1/2 teaspoon pepper in a bowl. Stuff body cavity with onion mixture. Tie legs together with kitchen string. Lift wing tips up and over back; tuck under turkey. Brush turkey with oil; sprinkle with remaining 1/2 teaspoon salt and remaining 1/2 teaspoon pepper. Cover breast with foil. Place turkey in a disposable aluminum foil pan.
To prepare the turkey for indirect grilling, preheat grill, heating one side to medium and leaving one side with no heat. Maintain temperature at 350°.
Place 1 cup wood chips on hot coals. Place pan on unheated side of grill. Cover and cook 45 minutes. Place remaining 1 cup wood chips on hot coals; cover and cook 45 minutes. Add coals as needed to maintain temperature at 350°. Remove foil from breast; cover and cook 35 minutes or until a thermometer inserted in meaty part of thigh registers 165°. Remove turkey from grill; let stand at least 30 minutes before carving. Discard onion mixture and skin.
Place a zip-top plastic bag inside a 2-cup glass measure. Pour drippings from pan into bag; let stand 10 minutes (fat will rise to the top). Seal bag; carefully snip off 1 bottom corner. Drain drippings into a bowl, stopping before fat layer reaches opening; discard fat.
Place cider in a large saucepan; bring to a boil. Cook until reduced to 3/4 cup (about 4 minutes). Add pan drippings and Make-Ahead Gravy; bring to a boil. Cook until reduced to 3 cups (about 5 minutes).