i might be able to help with some things... you can figure out the rest...
first... If you want the mouse to move using the mouse movement while the middle button is down, then this example will let the mouse move forward if the mouse is moved up, and backward if the mouse is moved down:
thats just to show that it is possible. You can use the DarkGDK.IO.Mouse.MoveY and DarkGDK.IO.Mouse.MoveX to do stuff with the mouse's movement, it has to become a float value first to work with 3d coords.
it would be very easy if the camera had a MoveUp method like objects do, but it doesn't
... so just for an example i have created an object that works with the camera:
DarkGDK.Basic3D.Sphere CamGuide = new DarkGDK.Basic3D.Sphere(10);
CamGuide.Visible = false;
Then in the game loop:
DarkGDK.Camera.DefaultCamera.PositionCurrent(CamGuide.X, CamGuide.Y, CamGuide.Z);
the mouse has a property called DarkGDK.IO.Mouse.MoveZ
it works with the scroll wheel...
This should be enough for you to figure it out