Seven signposted walks of varying difficulty fan out toward the peaks from various access points around the park. The Bicaz Tourist Information Centre website has descriptions of each in English. Note that trails covering the highest elevations are generally closed from October to April and there's a nominal fee (adult 5 lei, child 2 lei) to enter the park. Contact Salvamont mountain rescue if you run into problems on the trails.
The quickest route to the top begins near the village of Izvorul Muntelui. A blue-striped path brings you to near the top, near Cabana Dochia, in about four hours (change in elevation: 950m). Alternatively, a red-striped path covers the same elevation change in about seven hours. The two trails allow for unique hikes during ascent and descent.
From Durău (elevation 850m), on the mountain's northwestern side, a steep track (red stripe, one hour) leads to Cabana Fântânele at 1220m. From there, the red stripe trail carries on to Cabana Dochia near the peak, or use a connecting path to reach a second trail, marked by a red cross. The cumulative difference in elevation from Durău is nearly 1000m.
Mountain chalets at convenient spots along the trails, including Cabana Dochia, allow you to break the climb into two days. The village of Durău has plenty of accommodation, including several pensions.
You'll find passable cooking at the mountain cabanas along the trails, though restaurants and grocery stores are few and far between in these parts. Stock up at shops in Bicaz or Durău before heading out.