Scrub pig with a stiff brush; rinse cavity, and pat dry. Stuff with aluminum foil. Close cavity with skewers and string, lacing tightly. Truss by bringing feet forward and tying in kneeling position with string. Place a firm ball of aluminum foil in pig's mouth; cover nose, ears, and tail with aluminum foil. Insert meat thermometer in thigh muscle; do not touch bone.
Place pig in a shallow roasting pan. Bake at 325 degrees for 3 1/2 to 4 hours or until meat thermometer registers 170 degrees, basting occasionally with pan drippings.
Transfer pig to a serving platter; reserve 3 tablespoons drippings for gravy. Remove foil from mouth; insert apple. Place grapes in eye sockets. Remove foil from nose, ears, and tail.
To serve, carve along spine, breaking backbone.