Getting back to Rome to catch international flight

I would never, ever plan to buy a separate ticket to fly into Rome on the same day I had a transatlantic flight from Rome. They could cancel that Venice-Rome flight and leave you in a very messy pickle.

The usual suggestion for an itinerary like yours is to head to Venice (or at least Florence) on the day you land in Italy and make Rome your last stop. Yes, it is tricky to know what would be a safe departure time for a train to Venice/Florence when you're arriving on a transatlantic flight that could be delayed. But it is better to guess wrong and have to buy a new, full-price train ticket (hint: Florence would be cheaper than Venice) than to have a problem at the end of your trip, miss your flight back to North America and have to buy a last-minute one-way plane ticket.

Take the train back to Rome the afternoon before our flight, get a Rome Termini area hotel, and take the Michelangelo Express Train to the airport in the morning.
Just be glad you're not one of the many outgoing travelers with 6:00 a.m. flights where they're just flying to other European gateway airports and sitting until mid-day until all the flights leave for North America. (Never book such a flight.)

"(Never book such a flight.)"

We did and it was not a problem. We had 9 hours between flights and took the time to explore Zurich. (PS, it saved us $2000 on business class tickets.)

You need to be in Rome night before departure
Avoid sort of wasted 1 night stay by heading to either Florence or Venice on your arrival in Rome
Put all your Rome nights at end of trip
No need to stay at airport hotel
Be at FCO by 8:15 am
Taxi is fixed rate 48 euros or Leonardo express 14 euros

No way would I try to fly from Venice to Rome to catch an am flight
Just getting to the Venice airport that early is a real pain- you'd have to be at VCE by 5 am I guess? no thanks

9 hours between flights is very different than less than 4, less than 1 when you consider a 3 hour check in time

The ideal thing would be to go to Venice on arrival day and work your way back to Rome and do all you Rome days at the end.

No way I would try the fly to Rome the AM of departure day .

With the challenges to get to the Venice airport for a departure around 6AM and then a transatlantic flight, that is a gruesomely long day

If rearranging the schedule order is not possible,, then its go to Rome the day before

If you have checked bags you are in even bigger danger of it not having a happy ending

My $0.02

I’d switch your days. My rule is to END the trip in the city I fly home from. Much better use of time. Those stay-by-the-airport nights are a total waste of trip time and just serve to end your vacation early. Your last night should be spent walking around an enjoyable place, with a memorable meal. Not in an airport hotel (serviceable but almost certainly boring).

So go to Venice or Florence on arrival, do your trip to Venice and Florence, then head to Rome for however many days you want there. Stay in Rome, go to the airport via taxi or train on your departure day. Easy.

"Those stay-by-the-airport nights are a total waste of trip time and just serve to end your vacation early. Your last night should be spent walking around an enjoyable place, with a memorable meal. Not in an airport hotel (serviceable but almost certainly boring)."

Not always. We had an early morning flight from Milan (Malpensa Airport). We spent the night at a hotel near the airport (about 15 minutes) that had shuttle service. There were several nice local restaurants near the hotel and we had a very good end of vacation meal.

I agree with the advice that you train to Venice and work back to Florence and end in Rome. If you had not already booked your flights I’d suggest flying into Venice and home from Rome. If your flight you already booked into Rome arrives in the morning you probably couldn’t get into your hotel or rental until later in the day anyway.