Well, I didn't get a lot written yesterday (about 2,000 words) but I did realise what it was that I had to write. So next time I have a writing day, I have a scheme to work to.
I spent a lot of time yesterday reading about income distribution in the early Roman Empire and how this affects our reading of the economic and physical location of the early communities of Jesus followers. The correlation is simple (in theory), namely if there are middling sorts of people in the communities, the likelihood is that the groups would have met in domus-style houses and could, therefore, have been larger than if the groups were mainly comprised of poor people from tenements. Furthermore, leadership in those groups would have come from the heads of the households in which they met.
Rodney Stark argues - on sociological grounds - that the key group attracted to the new movement (as to all new religious movements) were the aspiring but liminal middling sort of people that Justin Meggitt suggests did not really exist in the empire and were not in evidence in the Pauline communities.
The question I was investigating yesterday was whether the data as handled by Roman historians suggests the presence of a middling, aspiring group whose status was in transition (ie they were liminal in some way). I think the answer I found was on balance 'yes' and that gives me the framework for the chapter on economic location.
I think Graig (thanks for the comment) is right. I now have to write what I know and then go back and tidy it up.