From Zihuatanejo, take a La Unión-bound bus (M$33, 30 minutes) from the Petatlán terminal– it will drop you at the turnoff. Walk down the road a little way and you'll find a stop where vans (M$15, five minutes) shuttle into Troncones every half-hour or so until 7pm; some continue to fishing village Majahua, just north of Troncones. Some 2nd-class buses heading northwest toward Morelia or Lázaro Cárdenas will also drop you at the turnoff.
Taxis in Troncones offer service around the area (M$100 to Playa Majahua), to the airport (M$800) or to Zihuatanejo (M$500). A reliable air-conditioned cab is run by Victor's Taxi Service.