I used to be a Die Hard fan many years ago before they became not so good.
While my last couple batteries were Interstate from an Interstate dealer or once from a Firestone Tire store, I think that a battery from Walmart, if you can get a good one, would be a good place to go because you'd then have a warranty that you could use in anytown USA. Even small towns have Walmart.
I am not a Walmart fan, and I wouldn't want a Walmart employee swapping out my battery - I'd pull it out myself and carry it in. But when I'm traveling to small, rural towns, I see a lot more Walmarts than Interstate Battery stores. And they are open early and close late and open on weekends.

 

Interstate has over 90,000 locations across the country. At least one in every city and county.

But what you said is their problem: You don't know where they are. Most of their outlets are mom and pop garages, oil change places or a few chains like Firestone. And they don't always keep the hours that a Walmart does.

 

In case anyone's interested, the Odyssey 49 950 (my planned replacement):

HIGH 7.47
LONG 13.87
WIDE 6.85
94Ah

 

For my last battery purchase I bought a BMW branded battery (for my BMW) that cost less from the BMW dealer than the comparable Interstate battery was going to cost me.