Heart of Rome Walk

Its been a while, but I would give yourself around two hours for it. I have done it in the morning and also night. Both are great but I prefer the evening, when the fountains and piazzas are less packed; although the pantheon will probably be closed (go early just as it opens anyways to get it all to yourself). I have done the walk backwards as well but this was after doing it forwards- so I found it easy to trace my steps back. You can definitely plan MUCH more into your day than the Heart of Rome walk, lunch and snack breaks. enjoy!

Personally I consider the RS "walks" to be an outline for a walk, not a literal herd path route to literally follow. I like to explore and when I find a place that I am enjoying I take it in and look around, take pictures, people watch etc. If you treat the RS Rome walk as a parade march it's going to take you a few hours. If you use it as an outline for a walk, it can take you the better part of a day depending upon when you go. Will you stop for a gelato or a cannoli and people watch at the fountains? Will you wait for perfect lighting and for people to step out of the way for the perfect picture? Will you catch the changing of guard and listen to the band and watch the parade/ceremonies at the Pantheon? Will you find that bakery with the perfect bread and coffee and have a snack?
You can do it in a couple hours..yes, but maybe you shouldn't. Four of five hours is a better tempo.

I haven't done it yet, but I mapped it out on Google Maps. I don't know if this will be helpful for you. Click for link detailed walking directions, but keep in mind that after the Pantheon, this walking map route wouldn’t let me take Piazza della Rotunda northeast to Via dei Pastini northeast. It forced me to jog southeast on Via del Seminario for a little bit before joining up with Via dei Pastini. Other than that, it gives accurate directions for the Heart of Rome Walk. https://goo.gl/maps/zR5LQcB8Ebo

I have only done it at night, and it was still packed. It is very pretty, though, with everything all lit up!

Thank you everyone for your replies. All very helpful.