Your products sell well outside cities via distribution centers but inside city limits (the not-so-scientifically named "Doughnut Hole"), not so well due to customers buying from Mom & Pop shops.
What's the best way to gather market research on these Mom & Pop shops? How do we discover what they have that we don't, short of sending someone to each place? Is there a more cost-effective method?
How do we fill that marketing hole?
Are you talking about reaching end customers or reaching businesses with your product. The distribution center part of the question is throwing me off a bit.
I'd be very interested in this myself. Short of getting figures from various distributors on what is being bought by these shops (they have to be buying from somewhere) I can't think of any reliable resource for measuring what they are selling to consumer. I would imagine they are playing very close to the vest on their actual figures. And I would even guess that many times their actual sales figures go unreported anywhere to avoid taxes.
I put a call out on Twitter. Hoping someone will pop in with another suggestion.