@nashvillehifi, I think your plan of becoming a national distributor is a good one. If feasible, imo it would be a good idea to route all sales through your dealers. Dealers don’t like to compete with their distributors, but they really appreciate a distributor "giving" them a sale.
My instinct is that a modest brick-and-mortar audio store is unlikely to thrive in a small town even if it’s an affluent town IF it is entirely dependent on local sales. I definitely sympathize with your dream of doing what you love.
Is there a way you could "fish from a bigger pond"? Is there a brand which is not available in the US at this time that you would really like to represent? I’m trying to think of a way you can have something unique to offer, so you can sell to upscale customers beyond your locality, but without having to compete with the internet. If you have something unique and desirable, you can theoretically generate sales well beyond your locality. Maybe something like Zingali (from Italy)?
Very best of luck with your endeavor!