I Must Survive by Harry Simpson III:
Brad Howard’s PBR is ambushed, his crewmates killed. He is stranded, alone in Vietnam. To survive, he must find his way back to friendly South Vietnamese soldiers or American troops. His only chance is to avoid starvation, as well as, all Vietnamese. They could all be Vietcong or North Vietnam soldiers.
To keep from being overwhelmed by the loneliness of nights and the constant fear of detection, Brad takes his mind back to his youth. Back to the hardships of his poor family and their experiences on the Great Plains during the 1950s, a historic time for our country when children enjoyed the freedom to roam without fear and had to use their imaginations instead of expensive toys and electronic devices to have fun, learn, and grow.