The Twin Sisters Traverse is a classic scrambling route in NW Washington. It includes great running and scrambling, and travels across to the more remote east side of the range to cross the Sisters glacier. The scenery and terrain is beautiful. The rock is mostly olivine, one of the few places where significant amounts of it are above the Earth's crust, and it's very sticky and easy to climb on.
The loop can be done clockwise or counter-clockwise, starting and finishing at Dailey Prairie and includes the North Twin, the the North Twin false summit, the South Twin, a crossing of the Sisters glacier, and the trails accessing the west ridges of both mountains.
There are multiple reports describing the traverse on https://cascadeclimbers.com
The most common access to the start at Dailey Prairie is via a gated road off the Middle Fork of the Nooksack river and crosses private property owned by Hampton Family Forests (formerly owned by Weyerhauser). It is most common to bike up the road but motorized permits are also available via the property owner.
