I don't know if I would describe Rome as "very walkable", which is a word people use for Boston, despite the location of the Museum of Fine Arts and the Gardner. But we walked from near Piazza Navona to the long, slow line at the Vatican (i.e. very far), and enjoyed our observations along the way. You just have to plan in advance.
It's hard on a first visit to Rome to know what you want, but for example, a couple with a child or two might prioritze "running around" space like the Villa Borghese. An art history student might focus on a museum or two that they'll visit repeatedly. Another idea is a Metro station, although it's not a very comprehensive system. (We did need to get to Porte Mammolo for a public transit daytrip to Hadrian's Villa.) On our first visit, we loved being near the Trevi Fountain, but that's not really very important. (That was so long ago that our toilet paper holder had a shower-water flip-down cover. No curtain.)
Rick (our host) has sometimes mentioned less-touristed dining locations, like Monte, I think. But by the time Rick writes about them, they're a little busier, aren't they! That post about morning coffee is a useful thought, even if you pick a different location. (In that sense, the required coffee-pod machine in an AirBnB is an enemy of proper tourism.)