Are there any patterns to the power-up panels in the red mushroom houses in New Super Mario Bros. Wii? Is there a way I can tell where the Bowser/Bowser Jr. panels will be?
Each world has 6 possible panel combinations. There is a guide on GameFAQs detailing the different panel combinations, and which ones you should hit to test what the current arrangement is.
Also, here's a visual guide to the panels.