Remove giblets and neck from goose; reserve for other uses. Rinse goose thoroughly with cold water; pat dry. Prick fatty areas of goose with a fork at intervals. (Do not prick breast.) Lift wingtips up and over back, tucking under goose securely.
Combine salt, pepper, garlic, and ginger; rub over surface and in cavity of goose. Combine apple, onion, and 4 celery leaves. Stuff cavity with apple mixture, and close with skewers. Fold neck skin under, and place goose, breast side up, on a rack in a roasting pan. Bake, uncovered, at 400° for 30 minutes. Reduce heat to 325°, and bake an additional 2 1/2 hours, basting occasionally with pan drippings. Goose is done when drumsticks and thighs are easy to move. Discard stuffing mixture. Transfer goose to a serving platter; garnish with celery leaves, if desired. Serve with Baked Apples surrounding goose.