I think you need to think through very carefully about having a shop, especially one which is open for long hours.
Who would man it? If it was you, who would do your smallholding work? If you employed someone else, you would of course have to pay them. If it was a co-op then each person would have to spend less time there doing their share of the manning, but would it be economical and would you be left holding the baby when the others had given up on the idea? How much of your capital would you need to invest in order to have a decent choice for customers right from the start?
Realistically, how much profit would you make? How much trade would you get? Would people come to you just for a few odds and ends, like a corner shop, but do their main purchasing in a big store further away, or by mail order? How many smallholders live within a distance which would make your store sufficiently local and convenient to woo them away from the larger places?
A shop such as you are suggesting opened in our local town and at first it did a fair trade, but then they appear to have found it uneconomical as people never bought much in each visit, just things they'd run out of. The price you charge would have to be relatively high as you can't benefit from bulk buying (storage and sell-by dates) so your overall turnover is likely to be low, and wastage or 'sale prices' frequent.
My feeling is that it might be better to encourage someone who has a shop already, such as your local pet or hardware store, to stock smallholding supplies as well. They will always be looking to increase their customer numbers. That way you can benefit from the advantages but don't have to commit your capital and time to an enterprise which is never going to make you rich.