The summer is almost over... Gaming season begins soon.
I am preparing the second part of adventure 3 (luckily it just was released for 5e) and I am also preparing adventure 4. As you might remember my group extinguished the Seela and made the wood burn down. So now when the Ragesians march to Dassen there seems to be no need to use the Alydi Gap to Gallo. As far as I can see it the Ragesians could now just march through the remains of the burning forest. So what to do? Change the locations? Let just a scouting group come through the forest while the main part of the army uses the Gap? I´d like to make their decisions have an impact on the future.
Thanks in advance!
Keep in mind that my advice is only for the adventures as they are written, not for how you make it your own.
Up through adventure 9, the Second Ragesian Army has only made it through the six western districts of Gate Pass before they are defeated by the Resistance. They needed to make it to district 11 to be able to bring an army through Innenotdar. So the Ragesians are not really going to have a chance to actually use that route. The Third Ragesian Army's actually has two missions. They are going to destroy Seaquen, but they are also going to take over Dassen on the way after all the leadership is dead. So they are not going to march several hundred miles away. Their route lies through Dassen.
Also, a few things happen in adventure 4:
1. In act 2 Lady Timor is royally pissed that the route through Innenotdar is opened (regardless of why) though it doesn't affect whether she helped.
2. In act 3 the heroes run into some Tragedies and will recognize what they are and that Balan (and others) are dead.
3. Also in act 3 Serrimus is going to send a message to Guthwulf that hints the path through Innenotdar might be opened. So the heroes have a chance to slow down how quickly the information makes it to the Ragesians.
As for running into a scouting group, it might be a bit contrived. The heroes will take the western route to Bresk. A Ragesian scouting party would be hundreds of miles away.
Remember that the adventures were meant to be a bit modular in that each one is in a different location. So if Innenotdar falls, or Dassen descends into madness, the campaign saga can still continue. The success and failure of the heroes throughout the campaign is accumulated through Victory Points in adventure 12. You could add a -5 for the forest being burned down and represent it by Dassen sending a smaller army because they kept more soldiers at home to protect the northeastern border.
Honestly, the sense of failure about what happened is the biggest thing the heroes will carry with them. It will shape their decisions as they move forward and may save the royal court as they learn to dig deeper.