Recommend places to stay, and eat,things to do

RS does have a Sicily guidebook
https://store.ricksteves.com/shop/p/sicily-guidebook

For Bari:

Bari - Panifica Santa Rita - I went there last year, so I knew it’s worth standing in line again for this street food focaccia & frankly the entertaining experience! Take a ticket number, don’t bother Rino “the bouncer” with questions, and watch people lining a street block waiting an hour for their focaccia. The local in front of me ordered 12 rounds! I ordered 1/2. Gentile gelato was a worthy repeat, too - delicious! I’m enjoying trying at least one new flavor at each gelato shop this year.

I stayed at Palazzo Calo again because their location is perfect for the San Nicola Sagra events on May 6-8, and I like that my room is a spacious split-level with a sitting room, table, sofa downstairs and bedroom upstairs. It’s located just a minute inside the Bari Vecchio neighborhood. The design inside the building is modern with plexiglass walkways & greenery decor.

I hope you’re visiting other cities in Puglia besides just Bari!
https://community.ricksteves.com/travel-forum/trip-reports/3-week-italy-trip-to-puglia-plus-tivoli-rome-may-2025

All the major publishers cover Sicily, but Calabria is tough. I think you’re better off with web resources:
https://www.roughguides.com/italy/basilicata-calabria/
https://calabriastraordinaria.it/en
https://www.italia.it/en/calabria

How many weeks do you have? Train or car? Time of year?

I second Panifica Santa Rita. We walked past the first queue of the day before it opened when we arrived in Bari. Later that evening, we walked past the queue again on our way to find dinner. I told my husband that if there is a queue like this, we were getting in it. It was hands down the best focaccia we have ever had.

Third on Sta Rita!!

Lots of very good restaurants in Bari, and we found prices to be very moderate.

Where else do you plan to go in Puglia?
In Calabria??

There are guidebooks other than RS; I like the Rough Guides.