Today Brandon replied to some Reddit threads about his 2020 plans after he finishes Rhythm of War, and talked about the timeline for The Lost Metal! Hooray details, hooray Brandon being transparent with us. Please note that these aren't surefire things, and this is the "perfect world" sort of scenario. First up: looks like Rhythm of War is taking a week or so longer than planned, with its turn in date now being July 10th (it was originally July 1st).
The Stormlight novella, which will part of The Way of Kings leatherbound kickstarter tiers, will be up next. Brandon plans to write it mid-July to mid-August, beta read it late August, and then do revisions in early October. Lastly, the copyedit done mid-October, to get to people a month before Rhythm of War. To me this is a pretty tight timeline, and Brandon does admit things can slide and he'll try to be up-front about it. The novella may not be called Wandersail, as that is the ship's name, but this novella doesn't have to do with Hoid's story in The Way of Kings.
Later in the year, he will work on Skyward 3, then with the goal to begin The Lost Metal, the fourth Mistborn Era 2 story, on January 1st, 2021. After that, it's the fourth and final Skyward book, with a target for starting on Stormlight 5 the following January.
Also, Brandon wants to fit in a "quick draft" of Songs of the Dead (formerly Death by Pizza), and probably will push back a revision of The Apocalypse Guard a bit later.
So, you know, I'd say that after Rhythm of War finishes, fitting in a novella, Skyward 3, Lost Metal, Skyward 4, that's pretty productive for the time in-between Stormlights. That doesn't even include any of the other projects, like Apocalypse Guard, Songs of the Dead, Alcatraz 6, or whatever else that might pop up. Sounds good to me.
In case you missed it: Brandon posted a large blog post on The Way of Kings leatherbound Kickstarter, which has updated tiers from what we previously reported. The Kickstarter goes live July 7th!
Edited by Chaos