Easiest way to create a continuous shot effect using multiple cameras? Here is the Script:

Lets take the opening scenes of Hugo, of course the film bagged Academy awards, In the scene that starts by following the kid (Hugo), carries on and on for some time with many complex movements and dynamics and finally reaches at a decent close frame.

Yes, in the making it was revealed that it was 3 different boys acting the scene.
What I ask here is an easier way, or maybe easiest among the lot (in the sense of both production cost and human resource/effort) to imitate a continuous shot effect using multiple cameras.

I have heard from my friend (a professional CG artist) that it can be done using 3D techniques. It involves the creation of the entire stage (the area where the scene occurs in real film) in the 3D virtual space. and then intelligently filling up the cuts between cameras using this 3D virtual fillers.

I am really open to that idea. But, are there any real life (no virtual/3D) techniques to establish a continuous looking scene?
CG is probably the best bet.  Motion controlled cameras would be the second best bet, but it would still be pretty tricky as the real world has a remarkable ability to change subtly, but substantially enough to result in a jump cut pretty quickly.  Even if you could manage to stop the camera on something that is static, resuming the movement at the same speed would be difficult at best without a computer controlled camera.  

If you are able to have the camera stop movement on scenery in between, that might make a possible stop point, but it would still have to be done pretty quickly to avoid changes in lighting conditions that would be noticeable in the final shot.