I used a Verizon smart phone on the TransAm. My coverage wasn't always exactly as shown on the map, but coverage can vary from one block to the next. In some places, I could text but not call. In some places, I could text but not include pictures in my text. In some places, I could call but not email. In some places, I could email but not call or text. Flexibility is the key. I studied the map ahead of time so that I could warn my friends and family when I might have days coming up without coverage. On the TransAm, that meant eastern Kentucky, Mammoth Cave NP, eastern Missouri, near the Colorado-Kansas border, southern and central Wyoming, parts of Montana and eastern Idaho. When cell coverage wasn't available, I would look for unsecured Wi-Fi.