The Old Washhouse is totally perfect if you want to explore Rome by yourself. I have spend 5 nights there and I am very happy, that I found this apartment. It has everything someone needs, if they are in a different city and on a little vacation or a longer trip.
It is located in an nice neighborhood, which felt also very safe for me. You can get there with a little tram (yellow), which is super cute (& the oldest one in town, I think) and it brings you in 15 min to the apartment or the other way around to Termini station, where also the busses and the train for both airports leave. A 5 minutes walk from the apartment there is a supermarket, you have a really cute bakery with nice staff around the corner (I recommend the pastries with marmalade!) and also a little tabacchi, a bar and a restaurant.
The apartment is exactly as described by the hosts, really clean and cute decorated.
When I arrived, Sandra showed me everything and gave me some good information about things I could visit besides the normal touristic things. It was such a warm welcome! There is also an information sheet for the apartment and stuff about other areas of Rome - you will never run out of things you can choose to do!
I only recommend you to bring some house slippers, especially if you get easily cold feet as I do - and I forgot them :D but besides that, I was very lucky to be there and enjoyed my trip to the fullest!