Good Night, Irene by Luis Alberto Urrea

In 1943, Irene Woodward abandons an abusive fiancé in New York to enlist with the Red Cross and head to Europe. She makes fast friends in training with Dorothy Dunford, a towering Midwesterner with a ferocious wit. Together they are part of an elite group of women, nicknamed Donut Dollies, who command military vehicles called Clubmobiles at the front line, providing camaraderie and a taste of home that may be the only solace before troops head into battle.
           
After D-Day, these two intrepid friends join the Allied soldiers streaming into France. Their time in Europe will see them embroiled in danger, from the Battle of the Bulge to the liberation of Buchenwald. Through her friendship with Dorothy, and a love affair with a courageous American fighter pilot named Hans, Irene learns to trust again. Her most fervent hope, which becomes more precarious by the day, is for all three of them to survive the war intact.