Bear in mind. We enjoy walking through Europe's great cities...and we walked a lot! Probably 30+ miles in three days (four nights). We stayed a couple blocks away from the Colosseum in an apartment just off Via Labicana. We had a kitchen and there was a grocery store a block away. Easy access to public transportation along Via Labicana and in between the Manzoni and Colosseo subway stops.

Day 1: Colosseum, Roman Forum, Palatino Hill, Campidoglio (we skipped the Capitoline Museums because we had plans for Borghese Gallery and Vatican Museums), Vittorio Emanuele Monument, then walked most of Rick Steve's La Dolce Vita stroll but veered to Trevi Fountain -> Spanish Steps -> surrey ride around Villa Borghese and park for about 45 minutes, and finally Borghese Gallery. Carried lunch and snacks; random gelato while walking and pizza dinner near Spanish Steps. We walked everywhere this day; could have taken the subway back from Villa Borghese, but preferred the evening walk.

Day 2: Vatican Museums, incl. Sistine Chapel, Saint Peter's Basilica, Scotland-Italy Six Nations rugby match at Stadio Olimpico. Lunch in between St. Peter's and Stadio Olimpico. Dinner at the apartment. Random pastries and snacks along the street while walking. We took the subway to the Vatican. Could have taken public transportation to and from the rugby match, but we preferred the walk, especially the late afternoon/early evening stroll along the river after the match...and then popped by the Pantheon (outside only - discovered you need tickets and reservation and we were too late). View of evening lights at Trajan's column and Trajan's Forum and Augustus' Forum and Colosseum.

Day 3: Rome Temple visitors center and Church at adjacent Stake Center. Warning - there is lengthy public transportation travel to and from the Temple. Late lunch at the apartment. St. Peter-in-Chains Church, then Rick Steve's Heart of Rome walk, incl. Piazza Navona, the Pantheon (went inside this time), and the Trevi Fountain at night. Rained like crazy at the beginning of our Heart of Rome walk - definitely a memory! Late dinner at the apartment.

If we had stayed more days, we probably would have tried to visit the Trastevere neighborhood and the Jewish Ghetto. We definitely would have done a day trip - probably to Ostia Antica ...may be Orvieto. If you haven't been, consider also day trips to Florence and/or Pompeii using express trains. Florence by express train is fairly easy as a day trip from Rome if you plan ahead. Pompeii is an Italy highlight, but a really long day from and back to Rome.

FYI - You need tickets and a reservation time for the Colosseum-Forum-Palatino (same ticket); Vatican Museums and Sistine Chapel (same ticket), Borghese Gallery, and (now) the Pantheon. Book in advance! For the Colosseum, do NOT use the entrance directly opposite the Colosseum; instead stroll left past the Constantine Arch and down Via di S. Gregorio to the Palatino Hill entrance. Easy - hardly a line. There is also a less-congested entrance to the right along Via dei Fori Imperiali, but lots of foot traffic to get there and still a line.

Also, you need tickets and reservations to view the David statue at the Accademia Gallery in Florence.