>>>  Maybe there's a way to preview the whole canvas as you render, but I haven't figured out how if there is.

There is. Choose Render > Render in Background instead of Render > Render. 

The render will take place in the Render window, and you can pan around the scene while it's rendering. 

>>> I also like how it renders the whole scene at once instead of the panels.

That happens when "Progressive Refinement" is enabled in the SuperFly render settings. It will render the whole scene, starting off at lower quality but gradually refining it until the render is complete.