From the introduction:
No campaign is easy for a Dungeon Master to run but the Rime of the Frostmaiden Companion ("Companion" for short) is devoted to making it easier and more satisfying for you to run. By providing new hooks, variants, flavor text, as well as any referential information for creature statistics or magic items, this supplement should make for a faithful companion to keep at your side.
...
The Companion is quite formulaic; every chapter is designed to be easily digestible, whether you're a veteran reader or just diving into it mid-campaign.
...
While Chapter 4 is certainly the most cinematic chapter in all of Rime of the Frostmaiden, it is also the most poorly-written when confronted with the very rules established by this same module—namely, it's travel times for dogsleds.