Mounting and unmounting encfs is easy in command line, but I was looking for a solution of doing it in KDE during system startup/shutdown. Here are two scripts which uses KDialog for asking for password and displaying notices.
Add those two scripts to autostart in KDE (or to your launcher/desktop icons if you prefer to mount/unmount it manually):
It will ask for the password when mounting:
When successful, the notification in the corner should appear: