Heat oven to 350°F. In large saucepan, make stuffing as directed on package, using butter and water. Add cranberries and apples; mix well. Set aside.
Place pork roast on rack in shallow roasting pan. Fill cavity with as much of the stuffing as it will hold. Cover stuffing and bones loosely with foil. Spray 1-quart casserole with nonstick cooking spray. Spoon remaining stuffing into casserole. Cover; refrigerate until 45 minutes before serving time.
Bake roast 2 1/4 to 3 hours, allowing 25 to 30 minutes per pound, or until meat thermometer inserted in center registers 155°F.
Meanwhile, in small saucepan, mix apple jelly and cranberry sauce until well blended. Heat over low heat until mixture is melted and smooth. Brush roast with jelly mixture and bake any remaining stuffing during last 45 minutes of baking time.
Place roast on serving platter. Cover with foil; let stand 15 minutes. Remove strings from roast. To serve, slice between bones. Serve with stuffing from center of roast and additional baked stuffing.