I just built up a test two node clustered environment with Server 2012R2. Everything seems to be functioning, however, the default file paths seem inaccessible within SQL tools. Meaning, if I try to specify the backup location to restore, I get an error that I cannot access the specified path on the server (C:\ClusterStorage\Instance\SQL\...) - then then the file structure is empty after I select OK. If I create a database new, the files get put in the default locations fine as well as when I'm on the server, I can access the files fine via the CSV path.
My thought is, the SQL cluster is not communicating properly with the CSV. In my prod 2008 R2 cluster, the disks are a dependency of the SQL service while in Windows 2012 R2, it is not (since it is using CSV).
I followed http://blogs.msdn.com/b/clustering/archive/2014/05/08/10523860.aspx - which really doesn't differ too much than older versions of Failover Clustering.