Dollar General, the nation’s largest retailer by number of stores, with more than 19,000, partnered with New York-based mobile medical services company DocGo is deploying mobile clinics to fill care gaps in rural areas. Dollar General’s latest annual report notes that about 80% of the company’s stores are in towns with populations of fewer than 20,000 — precisely where medical professionals are scarce. A Clarksville, Tennessee, pilot program is getting mixed reviews.