The Taxi, Vatican City
After the metro closes at night, taxis are the only option to get out of the Vatican if you don't want to walk all the way back to Rome at night. A ride from the Vatican to Rome Termini station is about 8 Euros. I shared a cab with someone who also needed a ride to Termini so we paid 4 Euros each.
I was advised to take a taxi to the Vatican, as I have difficulty getting around on occasion. Unless I am completely lost, I prefer the public bus. The public bus system in Italy appears to be on the honor system. You purchase a ticket before you board the bus then time punch it when you get on the bus. The ticket is good for a specific length of time. No one ever checked for my ticket, punched or otherwise.
I was only in the Basilica,audience hall,museum,gift shop and postoffice. While sometimes a little more walking involved, everything was accessible - for me. Do not confuse that with being being barrier free.