This was the second Pathfinder Society module I played through, and for 4, 1st level characters, it was a real pain. The module made sense, and I got the time intensive element, but it was, overall, deadly.
For Tier 1, ouch. The GM let me have a look at the module afterwards and, wow.
Encounter 1's EL wasn't listed, but it could have easily been a EL 2.
Encounter 2 wasn't bad. It felt balanced.
Encounter 3 felt like it was designed to kill the PCs. I'm curious as to how many players didn't tie off gear, take off armor, and died when the boat flipped...
Encounter 4, again, doesn't list an EL. Nor does the trap have a CR. So, I'll assume the trap's CR is equal to the 1d3 medium sharks it summons. (An EL 2 or 3 itself, we'll be nice and call it CR 1). Add two more brigands (CR 1/2 x2) and the CR 3 end guy? I'm going to say EL 4, maybe 5.
Encounter 5 was a solid EL 3. However, by the time we reached it, resources were completely exhausted and it was far more difficult. A party without a cleric would die here.
All in all, the run of the module for 1st level characters is very difficult.
I would not run this for level 1 characters. Moreover, as it is the second Pathfinder Society module, it strikes me as being intended for 1st level characters when released, which seems inappropriate.
The writing, story line, and feel was amazing. I loved the feel of it. But the encounters. Ouch.