The Mount Adams (Pahto) Traverse is best started from the Killen Creek Trailhead, but you can start at the Cold Springs TH if you wish (looks a bit shorter). Either way, the FKT is TH-TH. This is sort of 1/2 of the "Infinity Loop".
From the Killen Creek TH, you do some minor route finding to gain the bottom of the North Cleaver. Just before the climb begins, you'll come to a small glacial lake and should refill your water supply here. There is some water just before gaining the summit plateau but it's quite silty. The North Cleaver has maybe one section of class 3 but it's mostly due to loose volcanic rock.
Once the summit plateau is gained, it's very easy to cross while avoiding any potential crevasses. Go down the south side of the mountain, the standard route, until you come to the junction with the Round-the-Mountain Trail. This trail will take you around the west side of Pahto until you meet the PCT. Once at the PCT, keep going north until you reach the junction with Killen Creek Trail and then it's four miles back to the trailhead.
This route is incredibly beautiful and aesthetic. Traversing the second largest volcano in the Pacific Northwest has a special feel to it.
