Italy - 23 Hours in Rome

Hi, I have a 23 hour layover in Rome in July and would love any advice about must-do's, must-see's, etc. I arrive at FCO at 7:45 am on a Tuesday and leave the next morning (Wednesday) for Zurich at 6:50 am. I'm all about powering through to make the most of my time, but I definitely want quality as well as quantity (i.e., not just running from site to site to check the boxes of "saw that!"). I also typically prefer to walk a city to the extent possible when I'm only there for a very short time since I feel like it gives me a bit of a deeper experience.

I read the threads on early-morning flights out of FCO and plan to find a hotel in central Rome and then to take a cab or shuttle service to the airport (probably leaving the hotel around 4 am right?). Any additional advice regarding hotels or the airport would certainly be appreciated too.

I know this is just a tiny taste of Rome but don't want to pass up this opportunity to enjoy it just a little bit.

Thank you!

If you want to spend the $$, join a tour. This is a highly recommended tour company over at Cruise Critic: http://www.romeinlimotoursharing.com/scheda_tour.php?url=/tours-of-rome/sightseeing-tours.htm&pname=&it=4.

If you want to DIY, express train from FCO to Termini is easy, just half hour and only 14 euros, relatively cheap. Cabbing yourself is at least 50 euros (that was our cost from Trastevere last month). Or, you can share a transfer with the cruise people for 25 euros. Don't think the train leaves early enough for you to catch your flight.

My personal ranking of top sites to visit in 1 day:
1. Colosseum
2. Borghese Gallery
3. Trevi Fountain
4. Vatican museum
5. Pantheon
6. Spanish Steps

Save energy and use the metro and bus networks - just 1 euro a ticket good for 75 minutes. Have dinner in Trastevere area - very quaint - and lots of gelati, of course. Reserve what you can online, and you can save time. We joined a guided tour directly from the Vatican museum and bypassed the line.

Consider buying a Roma Pass to avoid standing in lines at the sights you can visit with the pass, you'll need to visit two different sights to make the purchase worthwhile. Decide with of the two sights, if any you'd like to visit before you buy the pass. If you'd like to visit the Borghese with the pass you MUST make a reservation in advance.

The Roma Pass doesn't include admission to the Vatican, if you'd like to visit the Vatican Museums instead of the sights included in the Roma Pass; reserve online in advance to bypass the lines.

If you take the express train to Termini, it is easy to get to most of the tourists sights from the stn either bus subway or by bus. Bus #64 is popular with tourists as it is frequent and hits many of the main tourist spots. Be super careful with pickpockets on bus #64.

I wouldn't try walking from sight to sight, you're best off taking public transport and visiting the sights (from inside) that are of particular interest.
Another reason to familiarize yourself with public transport options is that Rome can be super hot in July - walking from sight to sight could be unpleasant especially if you need to walk uphill.

I'd recommend a stroll around the Trastevere area or the Spanish Steps/Trevi Fountain area in the evening.