Wait, you are worried about <100MB program and data? You would have luck with your internet cache (should be moveable), your pagefile (might help with a second device for use, might hurt since slower device), or WOW's data (not sure how to do it, just seems like the hugest part of WOW is the data).

I guess the expensive fix is to get another SSD and put programs only on it with your OS on your first one. What happens when other games comes out and you want them to run fast? I personally went with raided 10k rpm drives. Sure like $150 each, but I like that they shouldn't wear out. I thought that SSDs wear out the more you use them. Not sure.

I guess I am not much help. No harm meant.