Huaraz is approximately 8 hours coach drive from Lima; it's simple and a reasonably cheap and reliable service. Movil Tours, Ormeño, Cruz del Sur and CIAL are most frequently recommended bus companies.
When you arrive you will find out that ´captadores´ are trying to bring you to lowly recommendated hostels and places. They spread bad words about the hostel you are willing to go to. Do not believe any of these popular phrases like: that hostel is always full, that hostel is far away. Especially at Cruz del Sur it is tough to leave. These 'captadores' get commision for each night you stay at the place that they recommend.
There are several daily buses to and from Chimbote & Trujillo. Movil Tours (http://www.moviltours.com.pe) & Transportes Linea (http://www.transporteslin...) are the best US$14, 9 hours to Trujillo, followed by Chinchaysuyo & Comite 14, all of which only travel by night, & continue to Trujillo. All night buses travel on the tar sealed road from Huaraz to Pativilca Caral is near there to the Panamerican Highway, midway between Trujillo & Lima.
Transportes Linea (http://www.transporteslin...), America Express & others run from Trujillo from 6AM or earlier to catch the 8-8.30AM bus of Turismo Huaraz & Yungay Express from Huaraz via Caraz & the spectacular Cañon del Pato. It's a rough 8 hour bus ride, the buses are basic for the unsealed road Caraz to Chimbote and may be overcrowded between Caraz & Huaraz. The views are stunning. Price is around US$7 S/. 25. If you have your own vehicle, obtain permission & confirmation of entrance times if maintenance is in progress from Proyecto Chavimochic in Trujillo Telefax 044 272286 or Viru to leave the Panam 485 km north of Lima via the well kept Brasileiros maintenance road alongside the canal to the north bank of the Santa River to Cañon del Pato. It is possible to cover Trujillo to Caraz in 5 hours + photo stops on this straighter, smoother road. Almost 40 tunnels are large enough for all but the largest tourist buses.
There are also day buses between Huaraz & Chimbote via the Callan Pass, Pariacoto & Casma for Sechin. Longer, rougher & not quite as visually stunning.
Every 20 minutes or so combis leave Huaraz for Caraz visiting Carhuaz and Yungay on the way.
