It is complex. I found myself going back and forth a bit too.
Most of the story/character arcs (of which there are many) are progressing simultaneously, almost relentlessly, throughout the story, and there are numerous unresolved (in this book) asides/events/subplots. There's a lot of exposition too, albeit "hidden" in dialogue. And then there's the sheer size of it. It's a complex read.
You can blast through it, picking up the story points; but if you are thinking it through as you go and living in it, then it's not a simple read.
On a more practical level, I drew a map and plotted where folk were, as the story progressed. I do think they should have included a map in the book.
On my second read, I'll be taking notes :-)