YIKES! We had a very nice place called the Cyclers' Cafe just a few miles from here. They carried great post-ride burritos. They went out of business last year.
ANyway, to your question:
1. Team up with a first-rate coffee roaster, someone who really knows the business. No Starbucks or Seatlles Best. Here in Louisville I'm thinking of a place called Sunergos. Even if the bike business is slow, make the appeal of the coffee high.
2. For little do-dads, most people go online. However, the problem online is you have to pay shipping costs. If you could figure out how to interface with the online shops in such a way as to save the customer shipping costs, that would be cool. I have no idea how someone would do that.
3. The bikes should be "sexy", whatever that means. Cyclers Cafe sold Felt and Kona, great bikes but not sexy (whatever that means). A sexy bike would be something like Volagi, plus they recently got all sorts of free press.
4. If you open shop in an aging demographic, consider carrying a line of recumbent bikes. If I had spare change, I'd bet on these. They are way easier on the 60 y/o body.
Hope that helps.
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Momento mori, amor fati.