Day trip I suppose means you will be in each city only for a portion of the day. Are you looking more for places for lunch versus dinner, or will you be staying late for dinner? (Since dinner seldom is served before 19:30 you'd have to be staying quite late for a day trip.) My thought is also that you have to be in/near the center of Rome. That said, I once was taken to dinner by 14 Italians at La Berninetta near Piazza Cavour and Castel Sant'Angelo. It was far from touristy and I had the very best artichoke I've ever had at this place. I do not know if they are open for lunch, but there is a contact form on their website. you could write to them. My favorite place that could accommodate you is far from the center, but it is La Fraschetta del Pesce. Fabulous fresh seafood from Anzio. No children under 5 allowed. I'll continue to think about it. Neither is "fancy."