After the fall of Harvest, the sun came out, and society began to rebuild itself. A new United Nations sort of organization was built to govern the new world, as it soon began to be called. There was a represenative of the watchers there, an elderly man named James Mcgraw. He sort of led the new grouping.
As for the scooby gang, Larry and Amy married soon after the fall of Harvests empire, and were personally involved with the destruction of Harvests' perverse tower. They had two children, a boy and a girl, and raised them happily in the new world.
Willow buried all the heros in thier own special places. She knew nothing of Spike, Dru and Angel, and so she buried them on the green hill with a large tree on it that replaced Harvests' tower when it went down. She also didn't know thier real names, and so had to bury them with those names she knew. Buffy was buried next to her parents in Sunnydale graveyard, Xander was buried there,too. Willow had some difficulty, but she found Ozs family and buried him with them. Willow then found herself the unlikely watcher of the new slayers. They came to Sunnydale(which was still a Hellmouth)and became the new slayers. One was a younger girl of Fourteen, and wa sa very religious girl. The other was sixteen, and loved modern art. WIllow helped train them, with help from another Watcher, and Larry and Amy. Soon, the scooby gang was reborn, and continued to fight evil on the Hellmouth.
But that is another story.....................