The book itself will have a specific section dedicated to the city of Terratorumme, complete with quest hooks, NPCs, and events to spark a campaign.
The digital adventure "The Sacrifical City" comes with pledge levels $20 and higher. It's something you could play for 2-5 sessions over the course of a level or two.
The boxed set comes with a longer, printed adventure "The Second Omen," which spans levels 1-5.
"The Desolation of Wellusk" is an extended adventure spanning levels 1-10 that was unlocked with one of the stretch goals. It's available to the Digital Oblivion ($45) backers, and backers pledging $60 or more.
The digital one-shots that are getting released with each stretch goal can be combined. Each one is at a sequentially higher level, so a DM can fill in some blanks between them to create a simple, quick level 1-10 adventure that spans the entire world (if we unlock all of them).