I'd worked in tourism for many years and am familiar with the working of hospitality. The stay at Gianluca's was top notch. Truly a lot of hotels (and other airbnb owners) could learn some tips from Gianluca! The place had all the right ticks and made our visit to Rome so much more pleasant.
The apartment has parking (don't worry - the apartment is located outside the ZTL area). We left the car and explored the city by bus and taxi but surprisingly mainly by foot. The Vatican was about 10 minutes walk and Pantheon about 30. Bus 64 runs through the main street and directly to Termini. Taxi cost about 8 euros (10 to Coliseum).
About the apartment - the air conditioner is a blessing during hot summer days! The kitchen is well equipped; washer for laundry and there's even a wireless printer available for usage, which we were able to print out Coliseum tickets. Gianluca also provided vouchers for free continental breakfast (x 1), discount for 2 restaurants and free Prosecco.
On a separate note, go try Scoop Gelateria which is just to the left of the apartment. Small place but fantastic gelato.