My party has just started book 4 and at the end of last session they arrived at the island. I've made tweaks throughout the campaign, such as the regatta being suspended due to the revelation of the spy ring plot arc that occurs over most the proceeding book. I also truncated the alchemist shop portion of book 3 and replaced it with a slightly scaled up and tweaked Tarin's Crown. The Dominator is still looming around as a menace on the hunt for pirates and the party has a healthy respect/fear of the ship. This brings us to the actual body of the thread, how I'm tying the three Islands of Plunder modules together into my S&S campaign. I figured I would post them here so that others can glean this thread for ideas and/or give me insight on to how to tweak this more!
It should be assumed from here on out that everything else is Spoilers both for Island of Empty Eyes and the Islands of Plunder series.
One of the tweaks I made in Tarin's Crown to tie it further into the story was that Tarin was a pawn of the Chelish spy ring and the goal was to smuggle the artifact out of the Shackles into Chelish hands. The Dominator was supposed to be the ship to pick up the artifact from Tarin and his erstwhile navigator (stat block replaced with the alchemist from book 3). The crew of the Dominator is now more determined than ever to hunt down the party and I intend to give the party the chance to have a throw down with the ship at the end of the book in place of the feast, but we'll get to that in a second.
Now, my party has completed Tarin's Crown and returned to Port Peril to report their success to Tessa Fairwind, who in my campaign is acting as their patron. Given that the regatta has been indefinitely suspended until a council vote brings it back, the party is pretty pissed, given that: a) Tessa was going to pay their entry fee, so it looks like she weaseled out of a deal; and b) they were informed of this by Harrigan, who hasn't blatantly acted out against them since the Wormwood but has been hounding them through agents throughout, though the party has no definitive proof of this. Since the regatta has been canceled for the time being, their is no in game reason for the party to be given the Island of Empty Eyes as a reward for it, so I've decided that Tessa Fairwind went there to try to influence Bikendi on a Pirate Council vote. In my game Bikendi is a reclusive Pirate Lord that no one's heard from in a number of years, so there's every reason for Tessa to head there. After some sleuthing around the party has made it to the island and found Tessa's ship anchored in the main bay completely abandoned, and here's where the main tweaking begins!
Since I want the Island to have a better tie-in to the overall narrative arc of the campaign, I've expanded a bit on the "haunted" premise presented with the old Chelish fort. I've also added Beacon Island from Razor Coast as a little side adventure for the party since we use slow advancement. Now, the next session is going to begin with the party's haunted dreams, wherein they will play out a small scenario. I will have the party experience the downfall of Tessa's one true love at the hands of his first-mate and a certain sea-hag who will become more important as I continue on.
For this I'm using a scaled up version of the second half of Spices & Flesh. We'll be skipping past the slave ship part and straight to the small isle at the end, with the objective being to seize the hag's dreamstone in order to tie it back into book 4. I've scaled up the encounters and retooled the hag a bit (She's now a Divine Sea Hag Knife-Master Rogue 8). The intent is for the party to drive her off and seize the dreamstone from her for Bikendi's research and then to flash-forward through the power of dreams to her forcing the ship they're on to run into the reefs surrounding the Isle of Empty Eyes. Here the first-mate, a one Dwali Kepu, will betray the captain and rename his ship the Wormwood. See where I'm going with this?
Later once the party has reclaimed or destroyed the dreamstone from the Cyclops ruins, they'll have a visit from the good ship Dominator. The reason for the rebuild of the hag is it's going to be revealed that the captain of the ship is actually the alias Shayonna has assumed over the decade since her defeat and is using her resources to hunt down what she believes is hers. The PCs will have received reports of their various holdings and allies having been attacked by the Dominator and that's when I'll allow them to track it down to the Steam Isle and have a final throwdown with the Chelish marines and its monstrous captain, and that will set the stage for book 5!
So, if you've made it this far through my long-winded ramble, I thank you. If you have any suggestions, questions, or tweaks, I would love to hear them!