There are only two ways to reach Todi from Rome: the easy, direct way, and the more involved way requiring two connections:
THE DIRECT BUS:
SULGA bus lines operates a DIRECT bus from Rome's Tiburtina bus depot (300 meters from the Tiburtina bus/metro station) to Todi, daily except Sundays, at 16:00 and taking two hours.
There are no connections and therefore no missed connections! This bus drops you in Piazza Jacopone, in the very heart of old Todi.
SULGA also has several other buses from both Rome FCO Airport and Roma Tiburtina bus depot to Perugia which stop close to Todi (but not actually in town), each of which requires a taxi ride to Todi proper.
The bus fare to Todi is 21 Euros one-way.
Children under the age of 2 ride FREE on the SULGA bus, while children between the ages of 2 and 12 get a 50% discount.
Luggage is placed in the underfloor compartment of the bus.
CONNECTIONS FROM/TO Rome FCO Airport:
Take the Trenitalia unreserved airport train between Rome FCO Airport and Roma Tiburtina Station for 8 Euros. Travel time is 48 minutes, and trains run every 15 minutes from Monday through Saturday, and every 30 minutes on Sunday.
The distance between the Tiburtina train/metro station and the Tiburtina bus depot is 300 meters.
If you plan to take the Trenitalia train out of Termini Station, there is a different Trenitalia unreserved airport train (the nonstop Leonardo da Vinci train) which takes 32 minutes and runs every 30 minutes. Service is guaranteed even during strikes.
Tickets for the airport train may be purchased from either the electronic ticket machines or from the manned ticket windows at the Trenitalia FCO Airport train station. Trenitalia has very recently added another ticket machine (and a manned information kiosk) on the arrivals level of Terminal 3. Note that you will pay a small surcharge if you choose to purchase the train ticket at one of the travel agencies in the terminal building or at the airport train station.
Airport train tickets MUST be validated prior to boarding, in the stamping machines at the head of the departure platform.
Children up to the age of 12 years, 0 days travel free on both airport trains with a paying adult. Extra children pay 50% of the adult fare.
(SULGA also has a bus from FCO Airport at 14:30 daily except Sundays going to Tiburtina and Perugia. You can take this bus and connect at Tiburtina to the SULGA bus to Todi).
The SULGA departure to Todi at 16:00 (Monday through Saturday) is workable for many passengers arriving at FCO Airport on flights before 13:30. But what if your flight arrives in the morning, and you have over four hours of free time?
If you arrive very early by plane at FCO, you could take the airport train to Termini Station, place your bags in the luggage hold, then visit the stupendous MUSEO NAZIONALE ROMANO across the square (both the Palazzo Massimo alle Terme and the Terme di Diocleziano, using the same ticket). After retrieving your bags, go to Tiburtina metro station by underground metro (1.50 Euros), then walk 300 meters to the Tiburtina bus depot for the direct bus to Todi.
There are also inexpensive airport BUSES to Termini for as little as 4 Euros if you don't want to pay 14 Euros for the Trenitalia airport train (but the buses take 60 minutes, instead of just 32 minutes for the train).
Don't arrive at the Tiburtina bus depot too early!!! There is nothing to do, there are no amenities, and there is nothing to see in the neighborhood.
CONNECTIONS TO TODI BY TRAIN AND BUS:
If you are determined to travel to Todi before the 16:00 departure time of the direct SULGA bus, you can take the Trenitalia unreserved regionale train from either Roma Termini or Roma Tiburtina to TERNI, and connect there to the Ferrovie Umbre commuter train to Todi Ponte Rio. Once at the Ponte Rio Station, you must take a taxi or the local bus to Todi proper. This is rather more involved than taking the direct bus, and there is the possibility of missing one or both connections. Here are the details:
Rome Termini to Terni by unreserved regionale train: 6.80 Euros and 65 minutes
Rome Tiburtina to Terni by unreserved regionale train: 6.40 Euros and 55 minutes
Rome Termini to Terni by reserved Intercity train (at 9:25 and 15:25): 16 Euros “BASE” fare and 50 minutes. There are also “ECONOMY” and “SUPER ECONOMY” fares for 9 Euros, but these are not sold on the day of travel, and must be purchased in advance. The Intercity train is a BAD DEAL compared to the unreserved regionale train on this route, under just about any circumstance.
Terni to Todi Ponte Rio: 3.90 Euros and 40 minutes by Ferrovie Umbre commuter train
(Distinguish Sunday schedules, which are less frequent)
Todi Ponte Rio to Todi Old Town by local bus (Linea C): 1.30 Euros and 10 minutes
(Distinguish Sunday schedules, which are much less frequent)
Remember to validate all tickets before boarding the train or bus.
A taxi from Ponte Rio to Todi will cost around 15-20 Euros, but you will probably need to call ahead, as none will be waiting at the station.
OPINION: The direct SULGA bus from Roma Tiburtina to Todi-Piazza Jacopone is the preferred solution. However, taking the two trains and the local bus is an option, if you study the schedules carefully and don’t miss the connections.