Take the taxi service if you think you'll be tired. I took a bus all the way from Termini to Trastevere (can't remember the number but you can ask) so didn't need the metro. 

Hi Stacey and thanks for your question! My advice is to follow your airlines' guidance regarding how far in advance to get to the airport. They are often the most up-to-date about current conditions regarding security waits at the airport.... (More)

Hi Tristan. I don't have any personal experience with transfers on this route, but for a group of 20 you'll probably want a private car service (NCC) booked in advance. Here are a couple I found through an online search:... (More)