[dnanian]

I'd swap the drives, clean install Leopard to the internal and -- assuming yoru crons and scripts are in your Home folder -- copy from the original when prompted to "Copy from another Mac".

Alternatively, copy using SD! ("Backup - all files") to the new drive, properly partitioned as "GUID" with "Mac OS Extended (Journaled)" as the format. Upgrade the copy to Leopard. Make sure it's as you want. Then swap drives.