Jimmy McCaffrey initially posted the route.  Over time the route evolved, and also there were some differences in exact routes taken by different people.  In late 2020 there was a discussion and agreement among previous FKT holders to determine the exact FKT route.  The route description below, and corrected GPX track, was provided by Chris Thoburn (Chris thanks Jennifer Walker for carefully proofing the new description, as well as to Kristina Randrup and Katy Pieri-McCaffrey for giving it a read for clarity.

http://www.wta.org/go-hiking/hikes/kettle-crest-trail

he Kettle Crest Trail is the granddaddy of long-distance, high-country routes in Eastern Washington. Over the course of its 44 miles, it presents a virtual highlight reel of dry-side beauty, from sage-scented meadows to subalpine parkland.

The Kettle Crest Trail is part of the 1200 mile Pacific Northwest National Scenic Trail, which extends from Glacier National Park in the east, to Olympic National Park in the west.

summitpost.org:

http://www.justgetout.net/Wenatchee/post/Enchantment-Lakes-Traverse

Isaiah Hemmen posted the route:

In Backpacker Magazine's "Trekking Washington," published by Mountaineer Books, the route is dubbed "The Grand Loop."

ROUTE: West from Deer Park to Obstruction Point; South over Grand Pass, Cameron Pass, and Lost Pass; East along the Dosewallips River; North over Gray Wolf Pass and up the Gray Wolf River; and North-East up the Three-Forks Trail back to Deer Park.

DISTANCE: 44.4 miles

GAIN: 14,124 ft