From Termini train station: take the A line metro (Red line) in the Battistini direction until Cipro Musei Vaticani stop. Turn right onto Via Cipro. Head over the roundabout onto Circ. Trionfale. After about 6 blocks, turn left onto Via Trionfale, the Happy Days hostel is at number 146, Green gate. (Please refer the photo with map on the 'Info and Rates' page.)
After 9pm there is a bus 70 on the Via Giolitti, take it til the last stop Piazzale Clodio. From there walk straight, after 5 blocks Via Trionfale is on the right.
<b>Taxis are available outside Termini but make sure they are official. (don't go with anybody who approaches you and asks if you want a taxi). Until 10pm the price should be €10 after 10pm, €15.</b>

From the Fiumicino Airport (Leonardo Da Vinci): there  is a train that leaves every 30 minutes, which will  take you to Termini train station; the ride is about 25 minutes.

From Ciampino airport: take  the shuttle bus that indicates  the Anagnina stop, then take metro Until Cipro Musei Vaticani stop (Battistini direction). Price for shuttle is 1 € and the metro  is 1€.