The night before her chemotherapy, Herlinda Sanchez sets out her clothes and checks that she has everything she needs: a blanket, medications, an iPad and chargers, a small Bible and rosary, fuzzy socks, and snacks for the road. After the 36-year-old was diagnosed with stage 3 breast cancer in December, she learned that there weren’t any cancer services in her community of Del Rio, a town of 35,000 near the Texas-Mexico border. To get treatment, she and her husband, Manuel, must drive nearly three hours east to San Antonio. So they set an alarm for 4 a.m., which allows for just enough time to …