Eternity Road by Jack McDevitt

Originally published: New York : HarperCollins, 1997.

When Karik Endine's expedition sets out to find the hidden sanctuary called Haven, no one believes he will return. The Roadmakers, the old people from before the 21st-Century Plague, left only ruins behind. However, Karik does return but alone, all of his team dead. When he dies, a rare artifact is found that inspires a restless young woman named Chaka to follow in his footsteps. Gathering together an unlikely band, Chaka and her comrades set out on an adventure-filled journey to discover the truth about their own mysterious past.