Is there a way to datadir= the bitcoin blockchain location? There is really no need for me to have two separate bitcoin blockchains present on my computer is there?
No, you don't need both... the credits wallet has both! You can send/receive bitcoins as well as CRE. Even if you only wanted to use Bitcoin, the Credits wallet is more efficient, seeing as you get full functionality for Bitcoin while having a greatly reduced size for your BTC blocks.
TL;DR : 4GB dir for BTC+CRE wallet, or 45GB for a bitcoin only wallet.