The description doesn't ring any bells for me. Only thing close is *way* different. an old story about the first interstellar ship from the 30s. It was a sleeper ship. and when they arrive, they find humans there. Seems the hyperdrive was discovered not long after they left. But because of the way it worked, it wasn't possible to catch their ship. so they arrive to a system that's been colonized for centuries..

the filk song "Space is Dark" is fairly close to the story. alas, the only online version I've found is played at *way* too fast a tempo. The original was slow and melancholy.

Generation ships of the sort that decide to stay out in space and only visit stars to replenish stores would likely evolve some interesting practices. probably a whole cycle of ceremonies for approaching a star and departing.