Thanks so much for the write up @
Nebulous. I am thinking of running PotA next after Lost Mines and this write up has really helped me. I have a few questions:
1) Given the amount of wrangling you had to do to make a purpose for the delegation, wouldn't it have been OK to just leave them out entirely? Why are they needed at all? Where do they lead the PCs to that is needed?
I'm not Nebulous, but I could try and answer some of these questions.
The Delegation is there as the initial hook, the thing that makes the PCs wander around the Sumber Hills and find the cults. If you can think of a different way of getting the players involved in the cults' business, then you could happily remove the delegation. I personally just ran the delegation as presented in the book, and my players (other than slight confusion over who was in the delegation) seem reasonably engaged with it as a directive. I also made them pick factions, so that their characters are here to do a job ('find the delegation'), which helps to make the delegation hook a little more important to them.
The biggest problem that I foresee is that the players will notice how the Delegation just drops off the radar as an important element as the campaign progresses, but that isn't necessarily a huge problem - the cults should rapidly become obviously the biggest issue in town.
2) Why did the cult use an Orb of Destruction? What have they made them for? What does the book say they are for? I loved the scene, but I don't know why they would use it on a town when the cults could use it on each other.
They use the Orbs for three main reasons, I think: to spread chaos (generic bad guy stuff, you know), to help upset the elements as part of summoning the Princes (though obviously they only succeed at that task at a dramatically appropriate moment), and to try and make the players piss off. They don't want adventurers snooping around, so they blow up a settlement to distract/scare off anyone nearby. Probably not the best plan, but then they are not exactly top-drawer in the sanity stakes anyway.
4) As written, what are the cults trying to do? why haven't they succeeded yet? I want them to be active participants, but other than recruiting I don't know what they are actually waiting for or looking for.
They want to summon the Princes of Elemental Evil to Faerun. They are mostly unaware of the Elder Eye stuff, I think, at least at levels below the Prophets. Their plan is essentially:
1) Start cult
2) Cause elemental disturbances to make a breach easier
3) Summon the Prince of their own element
4) ???
5) Profit
They are somewhat vague on steps four and five, but then the cults are stocked with madmen and monsters, who can convince themselves that elemental chaos washing over civilisation will only benefit them directly in the long run.
5) I want my players to be able to carry on PCs from LMoP to PotP. Would it change to much to allow 5th level guys to play this adventure? It seems that many of the issues are with people wandering into places that are too tough, maybe higher levels could alleviate this somewhat. Given bounded accuracy, would simply adding more of what each place has work well enough? e.g. 5 wind knights rather than the 3 it says are in a room. I am not too experienced with this in 5e.
Honestly, it would be the easiest thing in the world. What will happen is that your guys will be really hard at the start of the campaign, and easily overwhelm the enemies that the book suggests. You could beef up the combats without trouble though - as you say, just add a guy or two to each combat. But even if you don't, what will happen is that - since they are only getting the exp from combats appropriate for 3rd level - they will quickly catch pace with the adventure. Where a group of 3rd level adventurers would get enough exp to hit 4th and then 5th, your 5th level characters will get enough to take them... partway to 6th. And this will happen sometime during the first part of the campaign.
So my advice is simply to run the campaign without changes, and not worry about the initial discrepancy in player ability.