Is there any documentation/samples available for classes (especially GoDrawView) in Northwoods.Go.Draw namespace. Please provide pointers if there are any.

Not at this time; we’re still improving the functionality.

GoRuler and GoDrawView have been pretty stable. GoColorControl and GoColorForm is pretty stable too, from an API standpoint.
As far as GoDrawView is concerned, you can just use it as a replacement for GoView. Besides the two rulers, and the customized tools it defines internally and uses as replacements for the corresponding standard tools to update the cursors on the rulers, it predefines GoView.BackgroundHasSheet to be true and customizes that Sheet, which is a GoSheet described in the regular documentation.