Seeing as how I wrote this series of posts in a disorganized manner, it is only fitting that I end it with the starting point—the village of Saltmarsh, the party's home base while they tackle the series of modules U1–U3. Curiously, though the module describes the "little town" as playing a "pivotal role" in the series, with a "web of intrigue" that affects the party's progress, the village is given short shrift in the module's manuscript.
Instead of presenting the village and its inhabitants, the module hands the task of designing the entire thing to the DM, with advice to draw a map, establish the local businesses, and set up the town's council (and its conspirators). Some may see the omission of these details as a flexible advantage for homebrew campaigns, allowing the DM to put his stamp on the adventure; others may see it as a failure of the adventure designer to do their job. It's why you paid money for the module, right?
Interestingly, the basic "plot" of Saltmarsh is similar to the Sample Dungeon's "plot" of Portown (smugglers using nearby sea caves to run their operation, in collusion with local bribed officials), so those two pieces clicked together very well, along with new details from Zach Howard's Forgotten Smugglers' Cave adjunct. I took the background information from those three sources and crafted my own background "plot" to account for the various adventure areas of the site.
I started the campaign without a map of the village. Instead, I gave the party a handout list of the main buildings in town along with a brief description and details about what can be acquired/accomplished in each place. This was my tabletop group's first experience with playing early-edition D&D (Advanced Labyrinth Lord in this case), so I explained that town wasn't really a place for adventure but more of an abstract base for their characters to rest and reset between sessions.