From the where the Sisters Trail passes between the northern formation and the middle formation, face the northern formation and look for a rubbly gully that leads to the west ridge of the North Sister. Beginning at the bottom of the gully, climb the slab on the right-hand wall to a ledge below a distinct, steep crack on the headwall above. Build an anchor on the ledge to belay. Downclimb to descend.
Variation: From the same anchor swing the rope to the right on the other side of the boulder and arete. The right face is slightly harder (maybe 5.3 as opposed to 5.1-5.2 on the left side) but a little more aesthetic.
On the south face of the North Sister, just right of the obvious gully and directly below the steep crack on the headwall.
Medium sized gear. For the anchor I used a #3 and a #4 Camalot and slung the left edge of the huge block on the ledge. There is nothing fixed and nothing feasible to rappel from. You must downclimb to clean.