http://nwjeepn.com/WAtrails.htm#rimrock
Here's some usefull info Talked about some closures going on south of the lakebed towards the Tieton river .
http://www.fs.fed.us/r6/wenatchee/news/2010/07/06/index.shtml
The trails in the Rimrock Lake area are not for the novice off-roader. ANY of the trails that are listed as "More Difficult" can, and do, deteriorate to "Most Difficult" with changes in the season. Those listed as "Most Difficult" are designated as such due to their extreme hazardous conditions.
This area is known for very narrow trails, severe off-camber, and ridgeline trails that offer little or no protection for roll over and a long ride to the bottom if you mess up!
So, with all this in mind, make sure your equipment (Vehicle, recovery gear, communication) is up to the task and in good working order if you decide to take on these trails. DO NOT go alone!!! DO NOT go without recovery gear and be prepared (food, water, warm clothing) to spend a night on the trail if something goes wrong.
These warnings in mind, have fun, and have a safe trip.
This guy has alot of good vids at Rimrock must be a local
[YT]http://www.youtube.com/watch?v=eusNwwDerno&NR=1[/YT]