Convenience stores have long drawn regional fans.East Coast consumers are loyal to Wawa and Sheetz. The West Coast, to 7-Eleven. In the Midwest, there's a mix of popular chains with varying degrees of devotion, but Iowa-based Casey's General Stores, or Casey's, has become the third-largest convenience store chain in the U.S. by going after customers in small towns, mostly in that region. According to the company, 72% of its stores are located in towns with populations under 20,000 people, or communities tha ...