The Cassin up Cima Ovest di Lavaredo is a beautiful route, one of the classics in the Dolomites. Exposed and sustained climbing up to 7a, on fairly solid rock.
The ideal starting points are Cortina d'Ampezzo and Auronzo.
These can be reached from the north via the Pusteria Valley, or from the south by first taking the motorway (A27) to Longarone and then following the state road northwards. Both points of departure lead to Misurina, from where a private toll-road winds steeply almost to the base of the Tre Cime's south faces. Park the car at Rifugio Auronzo, situated at the end of the road and either sleep here or in Rifugio Lavaredo, reached by following the path for 15 minutes underneath the majestic South Faces which contain, amongst many other famous routes, the Spigolo Giallo.
From Rifugio Auronzo take path no.105 to Col di Mezzo and continue to the North Face. Follow the track across the scree to the base of the arête and start to the right, close to some scree ramps.
Reach the ledge and traverse right onto the South Face. Descend for 20m to a col that faces Cima Grande. Descend left into a gully, first left, then right, to avoid the boulders in the middle. Continue down the gully to the scree slope between Cima Grande and Cima Ovest.
There is plenty of in-situ gear, take numerous quickdraws, slings, kevlar cords, nuts and some friends.