Line two baking sheets with parchment paper. Set aside.
Combine cereals, almonds and coconut in a large (very large) mixing bowl. Set aside.
In medium-size sauce pan combine the butter, sugar and corn syrup. Cook and stir over medium heat stirring constantly until mixture comes to a boil. Continue cooking at a low/medium boil for 4 minutes, stirring constantly.
Pour over cereal mixture and stir until cereal mixture is evenly coated.
Spread mixture out onto prepared cookie sheets and let cool.
Pour back into a large bowl or into Ziploc bags.
Because I like mine more on the gooey side, sometimes I only use a little more than 3/4 of the box of each cereal.