Preheat the oven to 225° F. Lightly coat a large, rimmed baking sheet with cooking spray. Combine the oats, nuts, orange zest, and cinnamon in a large bowl. In a medium saucepan, combine the maple syrup, honey, and butter; heat over medium heat until the butter is melted. Pour the warm syrup mixture over the oat mixture, and mix to ensure that all of the oats are evenly coated. Spread out onto the prepared sheet pan. Bake at 225° F, stirring every hour, for three hours. Remove from the oven and let cool completely before stirring in the cranberries and raisins. Stored in an airtight container, this granola keeps for several weeks.