Adriatic worth a drive?

Never been to Bari, do some research for what there is to see.

You might consider Umbria. We are doing a week there next year, staying in Perugia.

Please clarify which coast you mean. Do you mean you'll be driving past Polignano a Mare, Brindisi and Otranto? That's not on the direct route to Sicily, but Puglia is a very interesting area with lots of great towns to stop in. You could easily spend a week, or more, tooling around that area.

However, from the map I suspect you'll be driving along or near the instep of the boot, past Marina di Ginosa and Policoro. I'm not familiar with that area, but if you go that way, Matera is a top stop along the way.

If you drive from Amalfi to Sicily going through Puglia that is a major detour.
Puglia certainly deserves a visit longer than a drive through.

What parts of Puglia would you recommend?

There are many attractive small towns in Puglia, some of which are just 2-to-4 hour stops, as much to absorb the atmosphere as to see a list of specific sights. Alberobello is touristy but on just about everyone's list because of the trulli. I based in Lecce on my too-short trip in 2015. It is a very handsome Baroque city with a considerable number of sights, including Roman ruins. It looks quite different from a lot of the coastal towns in that part of Puglia, which show what I assume is a Greek influence (white cubic houses).

Among the places often included on excursions, aside from Alberobello, are Locorotondo, Martina Franca, Ostuni, Monopoli, Gallipoli and Otranto. I'm sure I've missed some. I've read that Bari itself has a very attractive historic center, but I haven't been there.

acraven has given you good suggestions for the region, and I don't think you can go wrong anywhere in smalltown Puglia. We based in Lecce as well for 5 days, and in a few of the others for two or three days. There is plenty to see and do, and for us Lecce in particular was good because it's a nice town for eating, architecture, history and, of course, the evening passeggiata. It's been a couple of years since we were in Bari. It's Old Town is OK; it has kind of a labyrinth of old twisty, narrow streets, but you can get that in any Old Town in southern Italy. It does have an interesting history (especially WW II), but for me the crowds were off-putting, and the griminess and petty crime (especially after dark) were a turnoff. I felt like I had to be on my toes every minute. I'm always vigilant, and the typical travel risks don't bother me, but I was downright uncomfortable there. You didn't mention when you are going, but be aware that Bari is an increasingly popular port for cruise ships. You might want to check the schedules; a boatload of cruisers make the Old Town completely crazy. (Here's a sample for June 2020: https://www.cruisemapper.com/ports/bari-port-73?tab=schedule&month=2020-06#schedule ) .

If you really want to drive south and get off the beaten path, round the corner of the toe into Calabria and visit Reggio di Calabria for the Riaci bronzes.

It certainly like this area is worth spending some time there. Thankyou everyone.

We stayed in Bari old town and loved it thoroughly! We did not experience any discomfort at all and would love to return. We felt it gave us the most immersion into Italian day-to-day living than any of the other places we visited (which were many, over three trips to Italy). I'm sorry that Wanderlust58 had an uncomfortable experience there, but obviously things can happen to us anywhere. Maybe we have blinders on, but the only discomfort we've had anywhere in Italy has been the persistent/pushy immigrant vendors found in the more touristy areas.