Thanks will look into the trains
Currently I have two options
1. North (Rome, Florence/cinque terre, Milan & Lake Como)
2. South (Rome, Naples, Amalfi Coast)
Both options are great.
Read mixed reviews on Milan (some people say it's worth skipping) and Naples (you either love it or hate it (apparently dirty, smelly and overpopulated city areas). Then also read several opinions that Venice is a pass and so too is Pisa.
For us it was a decision between Cinque Terre and Amalfi Coast. We decided on the Amalfi Coast. Positano was the must-see here as this was a place on my bucket list.
Rome is a given. All roads SHOULD lead to Rome.

One need to do Rome at least once in your life and experience it. Great tourist attractions and vibey city life. Good metro trains which we used often and several hop-on-hop-off buses that also cover a big part of the city at a bit more but comes with an audio tour.
Must visit: Spanish steps, Trevi Fountain (early morning to avoid crowds!), Pantheon, Colosseum & Roman forum next door, Piazza Navona and Vatican city if that's your cup of tea.
Before we left I did a lot of reading up on the region and city specific foods to try out in each city/region.
For Rome it's definitely: Cacio e Pepe, Carbonara, Suppli, Amatriciana. And of course caffe (espresso) all over Italy. Best coffee in the world!
Florence was the one big surprise. We knew the city was going to be great but boy oh boy did we fall in love. Much more relaxed than Rome and more stylish (renaissance) and clean. Everything in easy walking distance. All tourist attractions easily within walking distance.
Amazing food, markets and views. Just loved it. Want to go back.
Must visit: Everything. It's all within close walking distance. Includes things like Ponte Vechio bridge, Uffizi gallery, Pallazo Pitti and behind it the Boboli gardens, Duomo cathedral , Piazza della republica, galleria del academia and stunning views off the city at sunset from nearby hill at piazalle Michelangelo.
Food to try in Florence: Pannini (especially at world famous Al Antico Vinnaio) (they also have other branches in Rome and Milan should you skip Florence - but it all started in this city and they have a wide selection here and several branches (4!) within the city centre. Lasagne al forno. Bistecca Fiorentina (huge t-bone steak). Chianti, Vernaccia or Brunello wines from the nearby Tuscanny area. Visit the Mercato Centrale (central food market) for a great experience of all the food the city and area has to offer.
Amalfi coast. Totally difference experience. Much more laid back. More touristy in places but still well worth the amazing scenery. It's another place I want to go back to. We only spent 3 nights there off which much of the day time was lost due to travelling (on the way there and back). We stayed in Salerno (technically not part of Amalfi coast - but about 1km from the first little town on the east (Vietri-sul Mare) and probably the best place to stay to avoid the high costs of staying in any of the Amalfi coast towns.
There's lots of little towns (13!) on the Amalfi coast to see and explore. Not too many large tourist attractions as the towns and their stunning views and scenery in itself is the attraction there. And the ocean and mountainscape of course.
Must see towns: Positano, Amalfi. Also worth a visit: Vietri sul Mare, Majori.
Food to experience in the Amalfi/Campania region: Polpette (meatballs), Pizza (Naples is just next door), anything with ragu, anything with lemons - this is the lemon capital of the world - such as limoncello, limoncello crema, delizia al limone (lemon-cream pastry).
Not recommended to drive here. The coastal road is on the side of the mountainscape (ala Chapmeans peak drive) and narrow with lots of traffic and restricted private vehicle travel on certain days. The Sita Sud bus service covers all the little towns and is an experience in itself!
Geez. This was going to be a quick reply and see how much I wrote. I friggen love Italy. Must go back.