There is an actual folder in your Library that holds the latest version of your iCloud files for specific applications (I'm not sure where, maybe someone can chime in).
However, I know that iCloud currently isn't supposed to act like DropBox. DropBox seems like more likely what you want (store files locally on your Mac, and have them in the cloud to access on iOS/Android/wherever). I love iCloud too but for some reason, Apple doesn't want an iDisk/DropBox for iOS.
There is an actual folder in your Library that holds the latest version of your iCloud files for specific applications (I'm not sure where, maybe someone can chime in).
I dragged the iCloud document folder for GoodReader (iOS) into the Dock to create a Stack which I can now easily use to exchange files between the iPad and the Mac.