Been thinking about this adventure some more and here's my latest high-level remix (with some hand-waving where necessary 
).
Leading up to the adventure PCs have established a reputation of being a useful team of urban adventurers, taking on odd-jobs for various citizens (and the city guard where necessary). Players should roll up characters with backgrounds and attributes that lend themselves to that end.
Level 1: As a reward for their most recent job they've been given the title to Trollskull manor but as it's known to be (at least) haunted they'll have to clear it out in order to make use of it. So level 1 is simply moving into Trollskull manor and basically setting up shop. I'd have the PCs start in Trollskull Alley staring at the ramshackle building they now possess.
Level 2: They'll get a few other jobs that introduce the players to life in the city (see the various excellent supplements on DMs Guild) and perhaps gather a few useful contacts that will come into play later in the adventure.
Level 3: They are visited by Renaer Neverember and asked to retrieve a stolen family heirloom (the Stone of Golorr - he makes up some story about how it was found when construction started on the City of Neverwinter by some ancient relative, it's been in the family ever since but was recently stolen as part of a general robbery.) Really it's as in the book, the Stone contains the location of the dragon hoard and Neverember wants it back without making a big fuss. This part of the adventure remix requires delving into the underworld of Waterdeep and tracking down the Stone - this can end with one of the chase scenes if desired, but it's not connected to the villain. Simply a black marketeer who thinks some other ne'er-do-wells want to steal from him/her). In the middle of this adventure occurring the news comes out of a great robbery of the city coffers.
Level 4: When they complete the job they find Renaer distraught. His father has disappeared and no-one knows what's happened to him. (In reality your chosen villain in the adventure rightly believes that Neverember has something to do with the theft of the dragons and have abducted him to find out where they are. This section of the adventure is to rescue Neverember and recover the stolen dragons. Rescuing Neverember is somewhat straightforward as the villain has discovered that Neverember doesn't know the whereabouts (thanks to the mind wipe) so they want to release him and then spy on him anticipating that he (or one of his agents) eventually leads them to the vault. This ends Level 4 with the PCs finding the vault and then having the villain take the gold instead (thanks to bringing overwhelming force). The journey through the vault will need to be beefed up quite a bit to make it challenging for level 4 PCs.
Level 5: Neverember commissions the PCs to recover the gold from the villain and return it to the city coffers via a magical portal (that he had originally used to steal the dragons in the first place...). If they choose to tell the city watch that the villain has the trove, then (off camera) the city watch attempts to retrieve it but of course the villain denies it and deflects back to Neverember (who is starting to be sweated by the city so really needs the dragons returned!). The city watch of course isn't able to find the hidden dragons. So the mission becomes find where the dragons are being kept in the villains lair and return them to the city vault without the villain knowing (until it's over). I.e. a proper heist.
).Leading up to the adventure PCs have established a reputation of being a useful team of urban adventurers, taking on odd-jobs for various citizens (and the city guard where necessary). Players should roll up characters with backgrounds and attributes that lend themselves to that end.
Level 1: As a reward for their most recent job they've been given the title to Trollskull manor but as it's known to be (at least) haunted they'll have to clear it out in order to make use of it. So level 1 is simply moving into Trollskull manor and basically setting up shop. I'd have the PCs start in Trollskull Alley staring at the ramshackle building they now possess.
Level 2: They'll get a few other jobs that introduce the players to life in the city (see the various excellent supplements on DMs Guild) and perhaps gather a few useful contacts that will come into play later in the adventure.
Level 3: They are visited by Renaer Neverember and asked to retrieve a stolen family heirloom (the Stone of Golorr - he makes up some story about how it was found when construction started on the City of Neverwinter by some ancient relative, it's been in the family ever since but was recently stolen as part of a general robbery.) Really it's as in the book, the Stone contains the location of the dragon hoard and Neverember wants it back without making a big fuss. This part of the adventure remix requires delving into the underworld of Waterdeep and tracking down the Stone - this can end with one of the chase scenes if desired, but it's not connected to the villain. Simply a black marketeer who thinks some other ne'er-do-wells want to steal from him/her). In the middle of this adventure occurring the news comes out of a great robbery of the city coffers.
Level 4: When they complete the job they find Renaer distraught. His father has disappeared and no-one knows what's happened to him. (In reality your chosen villain in the adventure rightly believes that Neverember has something to do with the theft of the dragons and have abducted him to find out where they are. This section of the adventure is to rescue Neverember and recover the stolen dragons. Rescuing Neverember is somewhat straightforward as the villain has discovered that Neverember doesn't know the whereabouts (thanks to the mind wipe) so they want to release him and then spy on him anticipating that he (or one of his agents) eventually leads them to the vault. This ends Level 4 with the PCs finding the vault and then having the villain take the gold instead (thanks to bringing overwhelming force). The journey through the vault will need to be beefed up quite a bit to make it challenging for level 4 PCs.
Level 5: Neverember commissions the PCs to recover the gold from the villain and return it to the city coffers via a magical portal (that he had originally used to steal the dragons in the first place...). If they choose to tell the city watch that the villain has the trove, then (off camera) the city watch attempts to retrieve it but of course the villain denies it and deflects back to Neverember (who is starting to be sweated by the city so really needs the dragons returned!). The city watch of course isn't able to find the hidden dragons. So the mission becomes find where the dragons are being kept in the villains lair and return them to the city vault without the villain knowing (until it's over). I.e. a proper heist.
