Very convenient location! I was in Rome for 14 days and walked everywhere! In addition, it is a block from Campo dei Fiori, where there is a farmer's market every morning and good restaurants at night.
Tommy was very helpful and easy to reach. He arranged a driver to pick my wife and I at the airport and to take us back when we left. I highly recommend you to do so too! He also offered us to arrange for rental bicycles, at a cheaper rate than most rental places. And his girlfriend was in front of the building waiting with the apartment keys when I arrived.
The apartment is not huge, but perfect for two people and has everything you may need during your stay. I would suggest not bringing too many things that must be hanged, as the closet is small and accepts no hangers. You can hang a few clothes by the bed, though.
The bathroom was functional and with very good hot water. Bring a soap bar with you. Tommy did have towels, shampoo and toilet paper ready for us. And some cleaning products too. By the way, there is a 5 kilo washer in the kitchen, but no dryer. I used it once, but probably better to save it for emergencies. There is a self-service laundry place two blocks away.
If you need anything, just contact Tommy, I am certain he will arrange it for you.
Other few tips:
Bring an adapter with you, especially if you plan to charge a cell phone or computer soon after you arrive, or ask Tommy to leave one in the apartment for you. They are cheap (1.50 Euro) and I am sure he won't mind doing so.
Read the email Tommy will send you with suggestions, it helps. There are a few guides in the apartment, probably left by other tenants. Use them!
Download an app or two to your smart phone, assuming you have one and sign for data roaming. I used 3, Trip Advisor, SayHi translator, and Ulmon Map of Rome.
If you need a hair dryer, buy one at home that is compatible with use in Europe and bring it with you.
Walk, walk everywhere and get lost in the streets of Rome! I hope you enjoy your trip as much as we did ours!