Paestum (45 minutes south by train or bus) holds three of the best-preserved Greek temples in the world, standing in a flat plain with almost no context around them. The site museum houses extraordinary Greek painted tomb panels discovered in the 1960s. A half-day from Salerno is enough.
The Amalfi Coast is the obvious day trip — ferries to Amalfi (1 hour) or Positano (1.5 hours) run from April to October. The ferry approach to both towns is vastly more pleasant than arriving by bus, and using Salerno as your base keeps costs down sharply.
Cilento National Park is less visited but worth it for those with a car — a large protected area of limestone mountains, river gorges, and wild coast stretching south from Salerno.
