If you want Symbolic Links...

Put the entire wow folder on the SSD.
Then put a copy of the wow folder on your normal drive, but delete the Cache and Data folders (possibly Interface too).
Create a symbolic link from the Cache (and then from the Data folder) to the copied Warcraft folder).

There are commands, which look like DOS commands /mklink something or other.
Or use the utility I found (which I used, prior to the SSD)... http://schinagl.priv.at/nt/hardlinks...kshellext.html

If you go with Symbolic Links.
Come patch day, break the links.
Patch the full copy.
Redo the links.
Then copy wow.exe from the parent/full (and patched) copy to the new folder.

In theory, the Data folder doesn't change much, but is what is read most of the time.
So having it on the SSD is the most benefit for speeding up warcraft.
With the least re-writing of data to the SSD.

Honestly, I just put all of WoW on the SSD, and did not bother with SymLinks.