Quest Line: Responders, Prerequisite Lead
After leaving the Vault, you'll get some information about the Overseer, who left before you and is exploring Appalachia. The C.A.M.P. base near the Wayward actually is registered as hers with a log, saying that she is going to Flatwood afterward. Follow her trail and it will lead you to the Flatwood settlement, where there is also the encampment of the Responders and a few traces left of what was once here. After acquiring her next holotape, your goal is to join the Responders, in the hopes of following behind her and catching up.
This questline will be the first of five main factions you'll come to interact with across the Appalachian wilderness. Follow this through to Missing Link, which will unlock two trophies and lead you to the next faction, the Raiders.