A couple of days ago I dug up the first Richard Corben storyboard page plus his roughs for his other storyboard pages for Conan the Barbarian. I thought you might like to see them, as they’ve never been published.
Each of the following images are two pages, side-by-side, except for page 13.
From what I can gather, Richard drew all of this in one or at the most two days. His graphic storytelling is so beautifully simple, clear and cinematic.