Friday night -- do Rick Steve's Night Walk of Rome, from Campo di Fiori to the Spanish Steps, to see the spectacular lighting of all the sites and do some people watching.
Saturday -- take the early morning (before opening) tour that starts in the Sistine chapel while it is empty. Are you planning a full day tour of the Vatican? if not, you could do the Villa Borghese in the mid or late afternoon. (the Borghese Galleria is spectacular and open to 7. You must get reservations for a specific time.)
Sunday -- perfect -- plenty of time for all you have listed. I would add going to the top of the Vittorio Emmanuale Monument to the list, as it is close to the Forum. The Arch of Constantine is right next to the Colosseum, so you can't miss it. Read Ricks' hints for not waiting in line to get into the Colosseum.
Monday -- the Borghese Gallery is Closed on Mondays! Revisit places you saw on the night walk -- Piazza Navone, Pantheon, Trevi Fountain, etc., and go inside places that were closed while you went on the night walk. Everything is different in the daytime. Be sure to throw your coins into the Trevi Fountain to make sure you will come back to Rome -- stand with your back to the fountain, and throw the coin from your right hand, over your left shoulder. (We did it wrong the first time we were there, but still got to go back!) If you have time, the National Museum has an excellent sculpture collection -- one of the best in Italy. If you have seen enough of the city, you could take a bus or tour to Tivoli.
We are going to Rome for a few days with our daughter and son-in-law in June, one day on a cruise (on which we will do your Sunday schedule) and three days after, and our itinerary will look similar to yours. This will be the third trip to Rome for my husband and I, so we know that this schedule is really do-able, and will leave us time to wander markets, have dinner at sidewalk cafes, and not exhaust ourselves getting around. We are staying in an apartment between the Pantheon and Piazza Navona, and our emphasis will be tracking locations in Dan Brown's book "Angels and Demons" because our SIL is a big fan. We are all very excited for our trip.
Buon giorno!
Jan B
PS I highly recommend MapEasy's Map of Rome for understanding where you are -- it has drawings of all the main attractions, so you can easily identify buildings and tourist sites. They also have them for Italy, Florence, Barcelona, and many other cities around the world.
