"In Sims 2, the young adults went away to University, were the active household in the University town, and then returned home on graduation. But I don't think we should assume it will be the same in Sims 3. We'll have to wait and see." from Schipperke
On the live chat, they said any of the adults (YA, adult, elder) can go.They'll be the active household in the University town, and aging will freeze or move slowly back home. They said they don't want people coming home to tombstones in the front yard.