End of Act I

The more I think about this setting, with the fortress and the valley, and with the competing agencies in the area, the more it feels like a stopping point. I don't mean the adventure is over, not by a long shot. This campaign runs up the river to an ultimate confrontation with a red dragon and its lair. This is literally just a stopping point.
Making the decision to use this as a stopping point suggests a few things. First, we can take another look at the entire story so far, with an eye toward revising it. For the most part I've tried to create an encounter per entry, but they've been written up as they came to mind, so they are more intuitive than structured or detailed. There is a value in reworking them with details and encounter balancing.
I like to jot down ideas, sketch out locations or interactions, then build detail into that framework.
Granted, I don't think the kind of work that needs doing lends itself well to this kind of journaling. So I think I'll work on it separately and post updates as I go.
I guess that I've just talked myself out of the stop I talked myself into last night. I'll sketch out an outline of what has happened so far and drop that in soon. To really sell this as a complete stage within the campaign as a whole, I can already see that more needs to be done to connect the initial encounter with the shrine to this cultist enclave. The dual magic items are a good start, but I think revising some of the bandit and goblin encounters to feel less random by making them connected to the cultists in some way will give the illusion that the party's actions against the shrine mattered greatly to someone unseen, and that there is a real threat from them.
Not every encounter, but enough to show a recurring theme. It may ease some of the concern I've had about the river making the whole adventure too linear. The threat of a chase requires linear movement. I do think the side trip to a mage's tower needs to be worked up and added into the encounter chain, probably between the bandits and the snow storm at the landing.
This should be a side trek into the hills to find and consult with the mage. This would serve two purposes, it would allow the party to gain more information about the artifact they found at the shrine as well as info about the cult itself, and it would allow the trailing cultists to overtake the party, causing them to cut across the hills directly to reach the fortress ahead of the party.
But, now we're back at wondering who the mage is, and what encounter can be built around them? The planar shift would work for skipping time ahead, or to explain the cultists passing them. I'm not sure it is the type of mage I'm looking for. I also think that since the purpose would be related to a dragon and an artifact of this world, an extra-planar consultant wouldn't have much to add. I think that is a better element to add at a later stage.
The questions to answer are: what does the mage know?; why is he a recluse in the mountains?; and what kind of encounter should take place?
Tomorrow, hopefully, some answers. Also, an idea of where the story should go from the fortress. It is time to start sketching Act II.