Explain Windows 8 Windows Store AppData/packages and what to backup
Solution 1:
Windows 8/8.1 automatically manages and syncs "C:\Users{user}\AppData\Local\Packages\RoamingState" data that is equivalent to "WinRT App roaming data storage".
Unfortunately WinRT App local storage is not syncing between PC and only this data should be placed in the backup. This data placed in "C:\Users{user}\AppData\Local\Packages\LocalState".