1. Preheat oven to 300°.
2. Place granola and pretzels in a large bowl; set aside. Combine peanut butter and syrup in a small microwave-safe bowl. Microwave at HIGH 30 seconds or until hot; stir well. Pour peanut butter mixture over granola mixture, stirring to coat. Spread mixture in a single layer on a jelly-roll pan coated with cooking spray.
3. Bake at 300° for 25 minutes, stirring every 8 minutes. Stir in raisins and cranberries; return pan to oven. Turn oven off; let mixture cool in closed oven 30 minutes. Remove from oven; let cool completely.