36 hours in Rome

What time is your niece's plane on Monday, and are you both flying out of Fiumicino? Any chance of just waiving dinner and meeting for breakfast at the airport instead? As it is, you'll need to be there by 10:00 if catching an international flight, and it's going to take you some time to pack up, check out and get there so your morning is pretty much shot for anything else anyway.

With just two nights/1 full day to work with, I wouldn't advise staying out near the airport or in Ostia. Central Rome at night is WELL worth sticking around for evenings strolls, and running back and forth from far outside of it would eat up a lot of time and energy. Oh, and you'll very likely use the buses far less than you think you will: what with traffic and where in particular you're going, it can be faster to walk! It's also MUCH more fun.

I second what Kathy said. Stay centrally and either skip the family meet up, have your niece come to the Centro Storico, or do the FCO meet up.

Buses in Rome are interesting. Usually in the central tourist area they run fairly regularly, but don’t hesitate to take a taxi (get one at the taxi stand or have your hotel call for one) as they are inexpensive.

The Vatican is always a zoo, so get a small group tour like with Walks of Italy. If you are interested in a private guide and your budget will support it, I can recommend Sonia Tavoletta. A private guide can really make the most out of your limited time and will customize a tour not only of the Vatican Museums and St. Paul’s but of other iconic sites like the Colosseo and Foro Romano. Expect to spend €55-60 per hour. LMK if you want Sonia’s contact info.

You sound like a candidate for the New York Times, "36 Hours in XXXXX" Check the NY Times travel section.

Walk! It's more fun. Stay in town. So much more interesting and convenient. Seeing the Vatican is amazing, but it takes hours. It's also somewhat overwhelming. As an antidote, my preference is to alternate indoor/outdoor activities. It keeps you fresher. You're less likely to feel worn down by an endless stream of museums. I'd suggest you give your self a good "big picture" look at Rome by taking the elevator to the top of the Victor Emmanuel Monument.

Is there any possibility of your niece and her luggage, meeting you in Rome, and spending the night with you? That way no one is in a rush to catch a train back to Rome or Ostia. Spending an enjoyable evening together.

Thanks for the good suggestions. It looks like it makes more sense for her to come into central Rome or to just catch up at the airport on Monday morning. Oh well! How often do siblings end up in Italy during the same time period (she with her university orchestra; my nephew and I separately)?! Thanks for the tips about getting around Rome as well. I'm a laidback, crowd-averse nature lover. Big cities and museums don't appeal much to me. I think we'll try to hit the highlights, including some of the outdoor sites, and just enjoy the rest of our time strolling around, especially in the evenings.