There are a stack of really nice places in Puglia which are worth visiting on route to Greece. Most ferries for Greece will depart from Bari or Brindisi.
If you are into Castles, the Castel Del Monte near Andria in Bari is an absolute must. It is quite close to Matera which is an amazing city and another must see. There are some great restaurants to recommend near both places and good B&B accommodation should be easy to find.
Trani is also lovely (and has an amazing cathedral by the sea), as is the coast from there down to Bari (Barletta, Giovinazzo, ecc). There is a romanesque cathedral in Bitonto which is one of the most beautiful and interesting you'll come across.
Both Bari and Brindisi have gained a bad reputation for themselves and in both cases it's unmerited. They both have heaps to offer. I've posted a link to a website with an article about Bari (go to the Media page and follow the link to Attrazione Fatale (don't worry it's in English too)).
Between bari and Brindisi, there is the amazing town of Alberobello which has to be seen to be believed. Ostuni, Cisternino and Ceglie Messapica are all really charming towns too.
Lecce (my home) is known as the Florence of the South for good reason. It's extraordinarily beautiful and around the province there are plenty of other really beuautiful things to see and do.
How long to you want to spend here?
Driving in Puglia was less stressful than I thought. Compared to the reckless driving in Germany on the "Autobahn" with no speed limit, it was almost relaxing. Just be extra careful on the narrow smaller country roads, especially at night, where stone walls and road bends often ostruct visibility.
I also second the tip of VT member fra.da to use a navigation system if possible (our rental car fortunately had one). It is especially helpful on the smaller roads. In general, Puglia was well sign-posted and we found each destination easily.
The only thing that spoiled our return from Puglia was the fact that we chose Alitalia as our airline. I had a bad feeling about this from the start, but the ticket price was OK and the travelling times seemed to fit into our schedule. Two hours delay on the first flight - that`s fine with me. But on return flight they switched the gates four times, we had a five hours delay, no explanation or apologies offered, nobody even available for questions, totally indifferent and incompetent staff, lousy on-flight-food, and finally they lost my luggage (sure they retrieved it the following day). I would never ever fly with Alitalia again - even on a free ticket. Alitalia must be the worst airline in Europe.
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