• In explorer go to C:\Users\(jason.coghlan)\AppData\Local\Autodesk\C3D 2012\enu\Template and create a new folder here.
• Once you have created that folder add the XXX.dwt to it.
• The go to your options in Civil3D and select the Files Tab
• Go down to where it says Template Settings, expand that out
• Expand out Drawing Template File Location - select the location shown and navigate to you folder created above
• Then expand out Default Template File Name for QNEW , select the DWT below and then set your DWT as the default.

Now every time you do a file new it will open in the folder with just your DWT in it. Also when you select on the QNEW icon in the top right corner to start a new drawing it will always start with the DWT that you have assigned in the options display.