Thread:Mainframebabe/@comment-27642721-20161009131008/@comment-27642721-20161009202620

You don't need to backup the entire LocalState folder, just the one file within: player.prf. It contains all your progress & inventory. It's importantance is obvious from the similarly named presence of player_backup.prf & player_backup2.prf. Although a local copy of your friendlist is kept with the "Social" subfolder (Friends_List.xml)