Peter, twenty-seven and unemployed, embarks on this journey to avoid his family, while Evelyn, a fifty-year-old biology professor, comes in search of a more visceral life. Ruth and Lloyd, veteran white-water rafters in their seventies, know they will never make this trip again. Jill, a stay-at-home mother with her husband and two boys in tow, craves the luxury of relinquishing control and following someone else's rules. Mitchell and his wife, Lena,...