Hey Beepster,
Here is another idea - just thinking out of the box.
You could use the laptop to connect to your DAW via a remote desktop connection.
For this to work you would need to have your DAW's lan port connected to a wireless router. Your laptop could connect wirelessly to the network from you vocal recording room and establish a remote desktop session to your DAW and that would give you full control of Sonar on your DAW from your laptop.
This way you don't have to tranfer your music between computers. You don't even need Sonar installed on the laptop
Of course you would still have to run a mic cable and headphone cable from your DAW interface to the vocal room. And you would have to set your mic and headphone levels at the DAW before using them in your vocal room.
Just thought I would throw an different idea out there.
Cheers,
Alex