Sooooo . . . .
Below may contain spoilers for Serpent Skull 3 so if you are holding out the opportunity to play it later don't read further.
I have been running S&S for about a year. We are stuck somewhere between book 2 and 3. I had added a lot to book 1 and 2 tweaked somethings. In particular I added a side quest pertaining to one of the characters back story pulled from Savage Tide (which I have used a lot of). The had a map to the City of Tamoachan I reskinned it as a lost city in the expanse and used the encounters from Savage Tide with a few tweaks. After finding the buried treasure (previous pirates buried treasure at the bottom of a well in the city). I made a passing comment that the ruins they found the treasure in were part of an "expansive collection of ruins." So the got what the came for and proceeded to get more crew from the ship and start to loot the larger city. I had already added a dynamic jungle chase from a horde of veggie pygmies and a pair of Girillons just to play up the jungle flavor. So they wanted to explore more of the city. I though an other encounter at them off the top of my head to burn the rest of the session time went home and tried to figure what to do. First I cut the Saughain dungeon and the encounter with the big plant. I had already thrown the Sargasso from Savage Tide in so no loss. Also I did not want an other under water dungeon so soon after bonewrack isle.
I knew Serpent Skull was sent in the expanse and that it has something to do with exploring jungle ruins. Sure enough part 3 City of 7 Spears. So I looked through it and started figuring out what to cut and so on. So much for pirate sandbox. The are not playing the part of jungle ruin exploring pirates.
I seem to recall one or two people using Serpent Skull and Skull and Shackles content together. I really liked City of 7 Spears because I did not want to find a gigantic jungle dungeon I wanted a ruined city with a few hot spots. If I had made it myself I would have probably gone for fewer hot spots but hey I can always cut content. I can also tweak things because they had already had some similar encounters so some city encounters were already done.
Any advice on dealing with pirates in the jungle exploring game and or using City of 7 Spears as a bridge from level 6 to level 7ish. I want to bring them back on line for the next chapter of S&S. I think I am going to have Isabella (who has already met them) chase them into the jungle. I introduced her earlier in the AP as a conwoman who used the PCs against the Lotus Dragons (part of the Savage Tide AP). I linked the Lotus Dragons to the Red Mantis as sort of an auxiliary front group. So I am going to have Locke who has conned her way back into the good graces or at least not dead by the hand of the Red Mantis chasing down the PCs. This gives room for a her as reoccurring villain while her stats are still viable. Having her find a Red Mantis artifact sword (treasure from City of 7 Spears) might also make for fun.