I really should have read this book first. It sets much of the stage for understanding the relationships of the characters in the later novels of the series (see my review of #2 which provides an examination of what is -- and is not -- real in the books: http://www.goodreads.com/review/show/674125216.)
One might argue Johnson sets a bit too much of the stage in this novel, sometimes sacrificing the plot. One element I thought was a bit over the top was the mystical Cheyenne component when Walt was trudging through the snow on the way to help Henry. And then the snow ceased to be an important element even though it was supposed to be a terrible storm.