Qualifier: I was a kickstarter backer.
I loved running this, the setting is very well written and clear. There are more than sufficient details to flesh out the start of this adventure, as well as tailor it to your own setting. Players can gather information in a multitude of ways, and if you feel like it, you can also adjust the time scale of the adventure to add or remove added pressure (My players were eager to set out, so I let them get to the destination and back to down before pressure started mounting).
I would estimate 1 session if the adventure is beelined (as happened with my players), but more likely 2 sessions if more thoroughly explored.