In other news, how should I, as DM respond to:
1. PCs assault an abandoned keep being used as a forward base by a commander of the enemy Horde, killing most, except their leader, Koth. They abandon the keep, leaving Koth in chains but unguarded. This is Day 2. Later that day, Koth escapes with the aid of other Hobgoblins that are just generally roaming the area.
2.They progress deeper, assaulting a Dragon guarding a Bridge the Horde needs to cross, but failing to do any real damage. PCs retreat. Mid day 3, shenanigans happen, and...