I apologize for double posting, but my post didn't tag Italy.

We've decided to take a ferry from Naples to Cagliari and then rent a car to explore the island.
We decided to skip Greece and we are staying longer here in Sorrento.
I've made reservations to Alghero for the 13th, but ferry straight from Naples it's only to Cagliari.
Soooo we would like to know what you recommend about beaches, more beaches as I'm renting a car in Sardegna and we will go to Rome before taking ferry to Barcelona.

Otherwise, logistically we could just do the reverse, drive or train first to Rome from Naples and take a ferry to Civitavecchia to Porto be in Sardegna last, then ferry to Barcelona.

Why don't you board your Barcelona bound ferry (Grimaldi lines) at Porto Torres, close to Alghero?
https://www.grimaldi-lines.com/en/ta...rres-barcelona

Yes, I think that's we will do.
We will train to Rome from Naples and from there we will ferry to Porto for a week in Sardegna.

No need to take the Porto Torres ferry. There are much more ferries to Olbia.