If you see the page as a container, containing lots of parts, then clearly the starting point can either be a NetWebPage or a NetWebForm.
Assuming that each of the parts are independent I'd probably start with a netWebPage. But it's hard to say whether that, or a form, would be better.
On the other hand, if you build the small parts, as various browses and forms, then bringing them back into a container later on is easy, and you can experiment with different containers.
So if I had to do this, I'd probably start by breaking the page down into parts, then deciding on the best part for each bit, and then bringing them together towards the end.
Cheers
Bruce