Currently I'm imagining prepping a set of small challenges (“fight off that incursion”, “capture one of these unkillables so we can study it and find a way to get rid of it”, “find the portal”, “cast a ritual to alert a nearby kingdom”, whatever), each of which has 0 or more other challenges (possibly connected by “or”) as pre-conditions.
@SPavel Yes. That would not be unexpected. We will need some player buy-in to start with, and a sufficiently low quota of characters prone to that.
(Also, good luck trying to ally with fey.)
The projector should show the end goal, the open challenges, the challenges currently attempted and the challenges completed, and by whom.
I'm thinking of the map of sectors in FTL, just it has to work for multiple groups and allow stepping back or sideways.
The penultimate column of challenges would be a column of things that need to be done in parallel (“close a portal”, “be a distractions”, “protect a breach in the walls”) with pretty deep dependencies.
To make it dynamic, the enemy might cross off challenges that could not be attempted any more at some rate.
(The last column would be the wrap-up and mop-up.)
This would mean structuring our prep starts by designing that penultimate column, and thinking about the conditions for each of these ca. 3 challenges.
In particular given I normally run low- or no-prep-games.
Every challenge of that column should probably be unlocked by 2-out-of-4 of previous challenges, where unlocking more than the 2 required ones gives a bonus.
The way I imagine it right now, I need a big projector screen that shows the progress, a way for GMs to communicate “challenge taken” and “challenge resolved in favour of the players” and “challenge resolved in favour of enemies” to that screen, and runners to get handouts with bonus information to the players.
Assuming that every challenge takes about … say, half an hour to an hour, with 4 hours total to fill, that's not running very often, that's a thing the a GM might be able to do himself.