GreyWord says:
Question if I may. Or checking the assumptions. I assume story will consist of two episodes the second being a log combat probably with multiple waves of enemy attacks, which would be a fantastic combat experience.
The question is about the first part of the story though. Are PCs trying to solve any social challenges (motivating commoners to fight maybe?), do exploration (scouting into enemy territory maybe)?
P.S. I am probably with WhtKnt there. I would believe there are better systems to tell story about "training the town". And I am surprised about a DnD commoner (even trained and equipped) to be part of a combat against CR 10+ enemies in DnD.
So yes, the first section would be those social/exploration type challenges for sure.
As for the DnD commoner vs CR10+ creatures situation. I have a solution for that which essentially abstracts their success based on how well the first part goes, sure there will be some villages in the crunchy combat but their success overall will be based on how well prepped the town is for the battle more so than attack rolls and saving throws that will also impact how the players' combat goes. The players will be the spot light.
