From Florence, we took a train to Salerno.
Once at Salerno, we took a ferry to the town of Amalfi. The ferries follow the Amalfi coastline so the scenery is pretty nice. These ferries are convenient as they run often and are usually right on time (in comparison to local buses as sometimes they are full by the time they get to your stop). If your travels permit, we recommend travelling the coast by ferry.