Here is the easiest solution I have found yet, courtesy of my tech guru friend, George Litterst:
Using DISK AID (software) on your MAC, navigate to STORAGE>APPS> GARAGE BAND>LIBRARY>APPLICATION SUPPORT>DOCUMENTS
There, you will see a complete list of all Garage Band files on your iPad.
NOTE: If you don't see all of these menu items, go to DISK AID PREFERENCES and check the box for SHOW ROOT PATHS FOR APPS
Once you see all of those files in a list, simply highlight all of them and click on COPY TO MAC, choose a destination folder and VOILA! They are moved to a folder within your mac or on an auxiliary drive.
NOTE: the danger in using iCloud (as mentioned in some previous answers) is that you may share your items with iCloud, but if you delete from the iPad, they are also deleted from iCloud. That brings up the biggest issue: iCloud does NOT function like MobileMe used to function. Be careful!