We are spending 3 nights in Salerno . For one day trip we are considering taking the bus along the Amalfi coast to Sorrento . then the Circumvesuvia to Naples, and the ES train back to Salerno. I"m not sure how long the bus takes, but Rick Steves said the bus ride is the best part of the Amalfi Coast. And we don't need much time in Naples - walk aroung, have some pizza.
But does this sound like a reasonable plan?