A local bus service does operate from Pescasseroli to Opi, Barrea and Civitella Alfedena - but a limited service, although enough to visit the towns under your own steam. Payment is made on the bus and is quite cheap -2 euros at the most to go to Barrea about 17 km from Pescasseroli. There is only 1 Taxi in Pescasseroli too!
For some of the walks we did as a guided trip who provided a mini-bus service.
So apart from that by foot is a good idea!
Service also exists to Avezzano and onto Rome - about 4hrs away.
Check the website link for the timetables.
Most of the roads and paths which pass through the protected areas are closed to traffic. Cars can only be used to arrive at the entry points of the Park, and to travel from one centre to another: excursions, walks and visits which involve contact with nature can only be carried out on foot or, for certain authorised trails, on horseback, by mule or by bicycle. In winter, cross-country skiing is possible.
Exploring on foot is best ..so look out for the footpath signs like this one....
Pescasseroli is equi-distant from Rome and Naples - about 160 km away.
From the north take highway A24 ( Rome - l' Aquila - Pescara) get off at Celano or Pescina and continue to Bisegna.
From the south take highway A1 Naples - Rome and take exit Caianello and continue to Venafro.