We have cruised out of Civitivecchia (port area) over 6 times. We have found that taking a private transportation service from Rome to the port being the less stressful method. I suggest searching post by @cruisemom42. She has so much info on visiting Rome from hotel locations, dining and excursion sites often missed by most travelers. We have stayed a number of times at the Lancelot Hotel which is in located 1-2 blocks from the Colosium and a number of small restaurants, shops, pharmacy within 2-6 blocks. Great family owed hotel with beautiful terraces and comfortable rooms. Have a great cruise and enjoy Rome.