Aldo’s apt is in a cobbled street , Via de Boschetto and very easily reached by Metro Linea B. In fact it is just one stop from the huge central Statio Termini. Watch for Laurentina direction and get off at Cavour. Follow Aldo’s directions from there but when you get off at Cavour you must cross Via Cavour and turn slightly left and you see another Metro sign down a set of stone steps. It’s easy from there, within walking distance, just follow Aldo’s direction. The apt is on first floor and Aldo was there to greet us. He’s a lovely, helpful host. The apartment has all you need including a washing machine and all other facilities you need. We were 2 females and felt very safe there. You can walk to most of the main sights from there. We did take a metro to the Vatican but can be reached in 30 to 40 mins on foot, I believe.
You need good flat walking shoes as streets are mostly cobblestones. I highly recommend Aldo’s apartment.