When Jeff makes A5 he should not bother recreating the whole of Avernum. As I'm sure he tires of making the same town multiple times. The adventure should begin perhaps at the Castle. From there the party could be sent to a newly discovered cave sytem that Averenties are just begining to settle. In short The Great Cave, Eastern gallery, and so on shouldn't really play a role in A5 as there are, I assume, numerous cave systems that could be exploited beyond these.