There is a Metro stn near to Frank's apartment so I would suggest who going to explore Rome to buy the Roma pass instead of hop on hop off pass. As the pick up/drop off point is not so near to the apartment. With Roma pass, u can easily reached the destination (with lesser walking).
We received a really warm hospitality from Frank's wife during check in. She gave us so many helpful info of where to visit, how to walk to there, where to eat with map.
But you need to bring ur own shampoo n shower gel as the bathroom don't have. Towels are provided, no worry.
The apartment also hv lift so no worry with your bulky luggage.