1. Preheat oven to 250°. Combine first 5 ingredients in a large bowl.
2. Cook honey and butter together in a small saucepan over low heat, stirring occasionally, until butter is melted and mixture is blended and smooth (about 5 minutes).
3. Pour honey mixture over cereal mixture, stirring to coat. Spread in a single layer on a lightly greased aluminum foil-lined 15- x 10-inch jelly-roll pan.
4. Bake at 250° for 55 minutes, stirring once every 10 to 15 minutes. Stir in raisins, and bake 5 more minutes. Spread immediately on wax paper; cool 20 minutes. Store in an airtight container up to 1 week.
Note: For testing purposes only, we used Quaker Oat Bran for toasted oat bran cereal and Kashi GOLEAN Crunch for multigrain cluster cereal.