my own campaign takes place over a fairly wide area, and because one of my groups has their own agenda that takes them traveling in and out of a series of different locales, I don't tend to run these strictly in order and one after the other as laid out in the book. If my players happen to be in Daggerford (Riverport), Scourge of the Sword Coast stuff might be going on. If they're in Saltmarsh (a short distance to the north), they will likely encounter stuff from Ghosts of Saltmarsh collection, and so on. So the adventures are interleaved with each other in an attempt to give my campaigns a more sandbox-type feel.
It should be noted I did not run Ghosts of Dragonspear Castle to start this. I just tweaked Scourge until it fit into my own campaign story. The intro starts with scores of refugees from the eastward countryside flowing into Daggerford seeking shelter and protection after being raided by orcs and goblins and having their towns and villages sacked. Meanwhile, the Duke is distracted by a feud he's having with a friend, who he has accused of stealing a dwarven artifact from his collection. As written, the players enter Daggerford amidst all this chaos. The first part of the adventure is all role-play, with players piecing together a story by talking to NPC all over the city.
For the Riverport Rebels, I ran the first introductory bit of this before I ran it for the Class of 81. (This detail will be funny later.) For their hook, it started out pretty straightforward. Refugees arriving in town, chaos ensues. Stephanie, Taijitsu, and Darren (Sir Peter has gone off on a quest of some sort...you know, paladins gotta paladin.) wake up in the morning intending to go out and try to help and figure out what's going on. However, they eventually start to realize an unfortunate development has occurred in the night.
And that development is that they have inexplicably been turned into dogs.* One of the Duke's enemies targeted them with some magic to get them out of the picture for a while.Nobody in this adventure as written gets turned into dogs. However, my husband (Darren/Sir Peter) thought it would be a fun thing to try. So I re-wrote the first part of the adventure, the part that takes place in the town gathering intel, so that they and everyone they had to deal with was a dog or cat seeing the event unfold through the situations of the humans in their world. So after being chased out of the Duke's manor by the Duke's steward, Regus, the three of them (Darren as a golden retriever, Taijitusu as a doberman pinscher, and Stephanie as a dachshund) hit the streets to seek out their friend Val, a local witch they frequently deal with. They went through a bunch of craziness to get her to realize that it was them and not pesky stray dogs, and she eventually got wise and used Speak With Animals to get the lowdown. To say she thought it was funny is an understatement.
For this adventure, I created a collection of NPC for them to interact with.
Among others, there was Fortunata the cat, from the Lady Luck Tavern, Timothy, a puppy waiting for his fisherman master having lunch inside a pub, Sarge, a guard dog at the city militia barracks, Sylvia, the pompous cat from the Duke's manor, and my favorites, a trio of aggressive stray dogs (Mofe, Bill, and Fluffy) led by a terrifying housecat named Killer Queen, who roamed the streets shaking down other wandering animals. (Taijutsu remarked that "Bill looks like he just got out of prison." He ain't wrong.) So the encounters laid out in the module happened more or less as they were intended to...just with this weird little twist. By the next morning, the Rebels were back to their normal selves, none the worse for wear.
For the Class of 81, I actually ran the intro part after they had run the second section of it that took place in the town of Julkoun. I also ran it on the same map after the Rebels had run the adventure, and on a whim, I left the cat and dog tokens scattered across the city map because hey, what city doesn't have its share of wandering cats and dogs, right? The Class ran this part of the adventure as written...they weren't turned into animals. However, they did notice that the map had a suspicious number of cat and dog tokens scattered across it, and in their paranoia began to speculate wildly about what that could possibly mean. Were the creatures cult spies? Criminal operatives in disguise? These thoughts seemed to ratchet up their paranoia to new heights, to my vast delight.
So anyway, instead of seeing all the refugees entering Daggerford and then getting intel and using it to head out to Julkoun (now overrun with goblins and orcs), they had gone through Julkoun on their way to White Plume Mountain, found it occupied, and then decided to clear it out on their way home. They didn't find out where the inhabitants were until after they'd returned to Daggerford. So I ran it more like a sandbox situation. A lot happened on that trip to White Plume.
But in either case, this intro section is set up as very much a sandbox, and the players are free to tackle their information-gathering however they see fit. The NPCs in town have their own agendas which will be in full swing as the players move through the town. It will take some effort on the part of the DM to make sure they know what will be going on when, so some studying ahead of time will be in order. There are a lot of characters and a lot of stories and info. One way I made this easier on myself is that I loaded a lot of basic information directly into the NPC character tokens on my virtual tabletop and left them simply scattered around the map, either on the main layer or on the hidden DM layer. Thus all I had to do to give myself a quick crib note was to click on the tokens so they'd give me an instant refresher.
*This impulsive dog twist was so fun and hilarious that it inspired us to create and publish a Roll20 Marketplace module, Westwind Garden, in which the players are transformed into a collection of different animals and sent to break a curse.