I assume the CoverFlow is inside a DataTemplate and this DataTemplate is given to the TileView's ContentTemplate property. To find the CoverFlow you will have to use VisualTreeHelper
which would significantly decrease the performance of your application. Instead, I'd recommend you use RadFluidContentControl as ContentTemplate for the TileView. The attached project demonstrates this particular scenario. Have a look at it and let me know if it is of any help. Additionally, this forum thread
explains how some properties of RadFluidContentControl work.
the Telerik team