In hindsight, I wish we had at least done an early morning side trip to Paestum. It's located in the part of southern Italy known as Magna Graecia, which used to be settled by the Greeks long before the Roman Empire. The ruins of Paestum are famous for their three Greek temples with massive, intact Doric columns dating from about 600 to 450 BC. All structures are built from the local bedrock--travertine. Also intact are the foundation walls of many parts of the ancient city, an amphitheater and paved roads as well preserved as the Appian Way in Rome.
The modern town of Paestum, just south of the archaeological site, is a popular seaside resort, with long sandy beaches where many Italians spend their Ferragosto summer holiday in the month of August. However, if you want to relax and enjoy the flavors of this region, make your hub in the beautiful port town of Agropoli... a seaport just to the south, with its town hugging the cliffs above. The town is definitely worth more than just an overnight stay. Some might call it a romantic getaway.
Another important aspect of the area is the raising of buffalo to produce the famous mozzarella di bufala. You may visit local farms to see the prized buffalo being massaged and pampered, as well as see how the fresh cheese is made.
If you go:
Catch a train from Salerno or Naples to Paestum station. Buy a two-way tick if you need to return. I have read that the ticket machines in the Paestum station rarely work.
There are ferrys during summer months from Salerno, Naples, Positano, Amalfi
Buses run throughout the Campania regions, especially in Avellino province, picking locals up for various points and taking them to the site for €9 return.
You can buy separate tickets for the archaeological site and the museum but if you're visiting both it is cheaper to purchase a combined ticket (about €6.50). There are various categories of discount. This is an Italian national monuments. Check for free entry for seniors and handicapped. The open air site is open daily; the museum is closed on the first and third Mondays of each month.