If you do choose to mine, I strongly recommend that you connect to Blaksmith's pool at geekhash, or run hozer's P2Pool code - the hashing there will speed testing and shorten the amount of time it will take to fully test the release.
If you want to connect to the test chain and see how it might affect you, back up your wallet.dat and catcoin.conf, delete the rest of the files. Then remove the addnode entries in your catcoin.conf and replace them with the master nodes: 107.170.40.107, 198.23.248.246, and cat.geekhash.org. The block as of this posting is 23249
Test chain? Can you please clarify what that means? You said you were on a testnet, but the geekhash node is part of the official list.