Making the Most of Your Time
If your priority is relaxing on the beach, plan on a few days at a seaside resort in one of the Gargano Promontory's fishing villages, such as Peschici, Rodi Garganico, and Vieste, and perhaps a further stay at one of the Calabrian coastal resorts, such as Diamante or Tropea, or Maratea in Basilicata.
Otherwise, choose a base like Polignano a Mare or Trani, especially if you land or dock in Bari. Take day trips out to the Valle d'Itria, or to the remarkable octagonal Castel del Monte. Then head east along the Adriatic route (SS16), stopping to see the idyllic hilltop Ostuni before continuing on to Lecce, where you'll want to spend at least two to three nights exploring the city's Baroque wonders and taking a day trip down to Otranto and Gallipoli.
Next, take regional roads and Via Appia (SS7) to reach Matera, whose Sassi cave dwellings are a southern Italian highlight; allow at least two nights here. Then it's back out to the SS106 to Calabria, along the coast dotted with ancient Greek settlements, as far as Tropea. At this point, cut inland on the SS107 across the Sila Massif, stopping at the hill resort of Camigliatello or carrying on to the more vibrant lowland Cosenza. Reggio Calabria is worthwhile just to see the celebrated Riace bronzes.