Puglia: beach and costal towns (also where the wedding will take place) You can choose a home base in Bari or Monopoli for 5ish+ days and take day trips to the other various cute towns (I'd recommend a rental car) - Bari - Polignano a Mare - Monopoli - Alberobello - Ostuni - Matera (I personally haven't explored this area of Italy so definitely check Pinterest hehe) -- getting to the wedding: rental car would be easiest! otherwise you can train from Bari to the Lecce Train station and arrange a transfer.
My personal fav region of Italy! All the good wine, beautiful art and amazing food! Florence (2-3 nights) - Duomo + art galleries (need to book tix in advance) - Piazzale Michelangelo for sunset - Osteria Santo Spirito!!! The best pasta in town (get a reservation) Tuscany (2-4 nights) - Will need a rental car to travel around. - Stay in a agriturismo (La Torre alle Tolfe is amazing) - Montepulciano - Siena (let me know if you need more recommendations for this region!) -- getting to the wedding: Fly from Florence to Brindisi arrange a car rental or an airport transfer
Incredible history & soooo much to do in Rome (3-5 days) - Colosseum + Roman Forum - Trevi Fountain - Vatican City - Trastevere for dinner + drinks -- getting to the wedding: Fly from Rome to Brindisi (1hr) or Train from Rome to Lecce (6hrs) and rent a car or get an airport transfer to the venue