1,2,9. ok so the PCs were to defend against the advancing goblin horde this Brindol, and were supposed to have not reached it yet due to being out fighting the goblins, but took it upon themselves to escort the refuges rather than let the NPCs lead them?
3. you added this spy person in while they were already off track escorting refugees when the NPCs were supposed to do it.
wait... why were the PCs not supposed ot escort the refugees..and if they weren't then how did they end up doing so?
seems that now is where it all got off track. was that weak hook for the PCs to go north the only thing that had them end up with the refugees?
you said you had been away from DMing for a while...so a reminder...read through and find weak parts of published adventures, as well as errors, and have fixes in place. NO published adventure is without errors.
6. as for reprimands it was the guard questioning the monk-paladin as to his actions of disobeying the city council or yourself? and it was you or the NPCs asking him about leaving the refugees to begin with. not sure what was in character or out, and it seems many int he thread view it as you asking the player, rather than in game actions questioning the monk-paladin, as well the way you present it and say the player felt "dejected" makes it seem as if you the DM is asking the player, rather than NPCs in game.
if it was the guards...well how did they know what alignment he was to even question? if it was you...you cant do that. you have to let player action run its course, even to the detriment of the adventure. if you invalidate player choice, then the players will become dejected.
yeah the guard/monk-paladin interaction seemed to be a big part playing into all sorts of later conflict with you and the players. the monk could have been acting within the law and good trying to get in and see why the city that the refugees were supposed to go to was turning them away. that sort of sets off all sort of plot flags and flashing warning lights to me.
Refugees: We are supposed to be here
Guards: You cant come in
PCs:
if the guards/city council were being controlled, then why would attacking them have made Pelor mad?
the PCs could easily see that something wasnt right and an unjustice was being done, and could have been responding to it in the only way you allowed for...at the time.
now i am not trying to side against you, just posing questions and trying to assume the player perspective, sicne you already know your own and knew more about what was going on, so that i could help shed light on what the players may have saw or been thinking with the limited information they have as opposed to all the information about what was going on that you had.
you tried to have the city ready for them, good...but things went wrong and now you want to amedn that. so you are trying to get ideas to fix the problem before tlaking to your players. all good.
just hope some ideas are helpful and let you see the other side as it were to be able to understand what they might have been thinking in case your disagreement could have been error on your part no matter how big or small as well as there so blame doesnt just get tossed back and forth.
i will see if i can find this adventure and read it to see what should have happened per it, and where maybe some things werent clear that may have confused you and the players.
i think the biggest sumbling blocks were the players escorting the refugees, and then when they reached the city.
and you might be right, your players may need bigger signs like a glowing hook to follow, or more subtle indications of when they get off the path if you are playing through a published adventure, and only have the adventure itself as what to run without other areas planned out outside of what is in the published product.
EDIT: ooh, and it isnt possible to forsee questions people may have to ask about things happening in your game, just like it isnt always forseeable to know what the players may do...so not presenting everything is why people can always ask quesitons letter to understand parts that may have been missed or left out. so no need to ever apologize for that as facts can come out over time to help clear up finer points.