Basically, a) I'm trying to understand your DMing style [where you fall on the wing-it vs. plan-it axes], and b) I'm trying to get a sense of how much background "ephemera" you have created for your lower planes (just what you need for play, or play details plus some sketch environs/surrounding contextual details that you round out as the directions/possibilities open [much like the original Q1 worlds for example], or a lot of detailed prep before play such that you can instantly throw Lehurze and Soneillon into the picture without any winging-it-like issues because you've already created and detailed them, their schemes and relations to the Loquai and Graz'zt, etc., etc.).
Generally I only prepare 1 session ahead in
detailed terms - wrt. "who" and "where." Things often fly off at tangents, and I'm forced to wing it.
There are character strokes which define the game, tho: For example, the initial Irknaan note says:
Irknaan: tension Rhyxali/Graz'zt (Soneillon?). Fierce pride/independence. Relations - Nhura (mistrust, interdependence); Shupthul (domination); Crosod (fear, occasional need); Samodoquol (caution). Utimately disdainful of demons. Opportunist. Aesthete. Erotic/sensual/powerful/dominating. Brilliant logician. Protective of the source.
Things tend to be detailed in terms of relationships: Graz'zt to Ainhorr; Tramst to Oronthon; Oronthon to Eadric etc. I guess when you have a fair conception of the way that characters are likely to interact, then the plot direction kind of 'looks after itself,' so to speak.
Timing is another thing - I generally make sure that if the players are about to make a big decision which changes the whole direction of the campaign (have a war, go to Afqithan etc.), then it falls at the
end of a gaming session, giving me time to pull the details together and fill in the gaps before the next time we sit down. It doesn't always work, and I end up winging it anyway - but as long as the
characters of the npcs are solid in my mind, I can usually maintain consistency.
A further difference is that the at least some of the worlds in Sep's version are demiplanes (Afqithan is explicitly named as such), whereas the worlds of Q1 were alternate Prime Material Planes. Perhaps in Wyre's planar cosmology other alternate PMPs don't exist?
I'm reluctant to give any definitive answer to that question.
It sounds like Afqithan has definite boundaries which are self-reflexive; I wonder if the inhabitants don't know that their world is so small and has such explicit boundaries and edges?
That was my conception also - that it is very definitely a non-Newtonian place, where space is stretched and reticulated. Any place in Afqithan is always at the centre, and the centre is always 1500 miles away from the boundaries.