I was all set to recommend backuppc, since it will automatically
backup whatever files you select, and it will keep various
versions of each file if it changes. However, you'll need
to set up a connection (SMB, NFS, whatever?) to the NAS
I'm amazed that you're saying the RH box can't connect to
an SMB/CIFS share. Try searching for smbclient. If that
is installed, you should be able to connect to remote shares.