Preheat the oven to 250 degrees. Combine the cereals, coconut and peanuts in a large bowl.
Line 2 large rimmed baking sheets with foil. Lightly coat the foil with cooking spray. Set aside.
In a medium saucepan over medium heat combine the butter, brown sugar, and corn syrup. Heat to boiling stirring constantly.Without stirring, boil for 5 minutes.
Remove from the heat. Stir in baking soda and vanilla. Continue to stir until the mixture becomes fluffy and light. Pour the mixture over the cereal and stir gently to coat evenly.
Divide the mixture between the 2 prepared baking sheets, spreading out evenly.
Place in oven and bake for 1 hour. Stir and switch the baking sheet positions every 15 minutes.
Remove from the oven and allow to cool. Stir every 10 minutes and gently break apart any large clumps.
When mixture is completely cool, stir in the M & M’s. Store in airtight containers.