Hi Michael
Not much to help I’m afraid, except for some musings on Puglia.
I’m assuming the route they’ll take will be via Matera for the cave dwellings. If they want a short but interesting stop just before, then Gravina in Puglia might appear a humdrum little place, but we found it friendly, plus they have a remarkable ravine splitting the town. Later on, Martina Franca worth a stop, but it’s so close to Ostuni that it’s probably better as a day trip (n.b. parking can be a bit problematic in Martina Franca, though we got very lucky on both occasions).
For food, the only place that I can remember, is the agriturismo/masseria we stayed at in Speziale Masseria Narducci | Agriturismo e Ristorante in Puglia From the pictures they’ve very much lifted their game on the accommodation, but the food was good back then and very much local/regional (even if that meant there was a tripe dish). We even lucked on a very enjoyable aged primitivo for €7 that was very much in the style we like (lighter alc% and also had some leather/barnyard).
For wineries I’d probably head down through Mesagne and onwards to some of the stalwarts of Salice Salentino: Candido, Cantele, Leone di Castris, but also try and mix in some smaller places that look promising (website searches can give a feel).
Aside from that, we liked Ostuni (albeit it’s a bit bigger than the other towns), Martina Franca, Locorotondo and Cisternino. Alberobello felt that bit more touristy, but is ‘trulli central’ if that’s a great appeal of the trip. We also didn’t think much of the coastal resorts near Speziale, much preferring Trani, but that’s up north of Bari. The Caves at Castellana might appeal, and appear very popular for school trips.
In general the driving in the region is super easy, with open vistas, and light traffic… punctuated with brief moments of more tricky driving as you pass through small towns, where the roads are narrower and the routing confusing. Then there are the bigger cities, which are generally best avoided for driving in.