We did basically the same run these guys are planning about a week ago.
Although we ran that portion of the Naches in the dark starting at about 10pm (wanting to get an "early" start on the trail . . . headed out Thursday after work) and set up camp in the first meadow by about mid-night.
If you're in a Jeep you'll make it.
Heck. . . we had a mid-80's Toyota mini-van on the trip with us who made it up the hill in the dark with the rest of us.
So, if the other guys wouldn't mind, I wouldn't hesitate on that run if I were you.
Manastash Ridge area
South of Cle Elum is the Manastash Ridge area, about 115 sq miles of fun trails and incredible scenery. Takes about 2-2.5 hrs to get there from Seattle. Trail maps are available here from my website in the "maps" folder
. Download and print at Kinkos on 11x17 paper.
As discussed briefly above. Takes you to the edge of the Manastash area from just outside Greenwater, WA (itself about 26 miles out of Enumclaw).
Liberty / Table Mountain
Some trails up in this area. Nothings "super difficult" I'm not that familiar with it and want to explore this area more. NE of Cle Elum off Hwy 97 around the town of Liberty, WA.
Fun ORV Park near Buckley / Enumclaw, WA. About 20 miles of trails put together. They run up and down the sides of some low mountains at the base of Mt. Rainier. Classic NW trails. So close to Mt. Rainier, in fact, that if you look down the valley of the one view overlook Mt. Rainier climbs up the other side. Body damage is very possible with the tight trail confines. It's more challeng, too, than other trail areas. But tons of fun.
Out past Monroe on Hwy 2 about 15 miles (+/-) . . . just on the other side of Goldbar, WA. I spent several months GPS mapping the trails (trail map available on my website). It's close. There are some easy trails. But there are also some very difficult trails. It's almost too much for me, especially after I bashed my Jeep on the rocks the last time. Oof. Sort of like Evan's Creek but more intense, and closer to civilization.
Walker Valley ORV Park
Up near Mt. Vernon. Semi-limited trail selection but fun trails, too. Some run through some clear-cuts, others through the woods. It's gotten a lot more fun in the last 2 years as the state DNR has opened more trails. It's definitely worth a half-to-full day of wheel'n and exploring.