Rome and Florence are in-land, but I'm sure you know that. Both can be reached by Civitavecchia, but it can be difficult to see in one or two days. Genoa is possibly the most beautiful Italian port that I've visited. Naples is beautiful, too, and near Pompeii if you want to visit. I've never been to Venice. I look forward to hearing about your trip! I've taken cruises arriving/leaving from Civitavecchia and from Genoa and I've taken the Italian trains, which are outstanding! If you want to see Florence and Rome, I'd suggest taking the trains. Happy travels!