Best time to visit is April May Sept or Oct. I planned my Italy trip on my own... booked flights on Skyscanner app, hotels on bookings.com and even sightseeing tours I booked online like Vatican City tour, Capri tour, Murano & Burano tour in Venice... I visited Rome with a full day trip to Capri, Florence & Venice with day trip to Murano and Burano. Even train tickets can be booked online on trenitalia site.
You can plan on your own:-
1)Check flights on skyscanner
2)Check hotels on agoda/booking/hotels/mmt/
3)check sightseeing tours on isango/viator/grayline/klook Venice, Rome,Capri Island,Amalfi Coast,Naples are must to be covered. Go anytime after May to July end.