Dangerous? Taking the eurostar between Florence and Rome? I've never "heard" anything regarding it being dangerous. What "dangers" are you referring to? If YOU were a single, young, untraveled female, perhaps any mode of transport in any city could be theoretically "dangerous" for you. But you're a couple traveling together, what is the "danger" you're concerned with?

I'd personally choose to listen to our Italian FTers regarding this, not someone in Florida (no offense intended, I'm just using common sense) - hopefully the terrific Italians who post in this forum will add their opinions as to the "danger" of taking a train at night. And you are aware there are now 2 train companies to look at, right?

http://www.flyertalk.com/forum/italy...-operator.html

and of course

Trenitalia

Regarding the question of spending a night in Florence, or just making a day trip out of it - it's very subjective. For me, I'd make a day trip out of it and avoid having to check-in/check out, pack/unpack a couple more times than if I just slept in Rome all 3 nights. I'm not very familiar with Florence (it's Rome I travel to often), but if Florence is indeed "dead" on Sundays, why not go on Saturday as a day trip? It's super easy since both train stations are within the cities' centers and the ride is only an hour and half.