Those wanting more info on this route can note the following:
The route we followed was 18 miles and can be found on Washington Green Trails maps 333 and 334. We left cars at the Tongue Mountain trailhead on F.R. 2801, where we would finish, and shuttled up F.R. 23 to the Dark Meadows trailhead. Follow the Dark Meadows trail west to the Juiper Ridge trail and then take that north to the Tongue Mountain trail and down to road 2801. It's a pretty straightforward route.
All in all, there's about 5,500 feet of total elevation gain throughout the course of the ride, despite starting at an elevation 1,000 feet higher than where you'll finish. We opted to include a side-trip up to Sunrise Peak halfway through the ride and the views from the top were worth the half-mile hike (just hide your bikes in the trees).
The next time I do this ride, I will be sure to 1) bring no less than 200 oz of fluids, 2) go earlier in the season before the trails are tore up by the motos, and 3) try to go after a rainstorm so the dust will be minimized.