Appia Antica Caffè
In addition to serving the usual array of sandwiches, salads, pastries, and gelato, this caffè—conveniently situated at the No. 660 bus stop on the corner of Via di Cecilia Metella—has teamed up with Bicycle Roma to rent bikes to use on the Appian Way and arranges guided tours (book via www.bicycleroma.com). There's lots of outside seating in the back, where your meal will be accompanied by birdsong.