These trails are officially recognized and signed by the Forest Service, and they vary in difficulty level. Liberty is a small semi-ghost town off Hwy 97 near Blewett Pass. There are a number of "Jeep Trails" in that area. Here are my thoughts on a few of them:
1. Although growing dated, I believe the best resource for these routes, including GPS tracks, maps, and descriptions is found at NWJeepn
2. These are NOT "overlanding" routes, they're fun, technical, and challenging. They're NOT suitable for all 4x4 rigs, or in all weather. If truly wet, they can be dangerous. If the operator isn't experienced, they can be dangerous. If the vehicle has mechanical shortfalls, they can be dangerous. These are aptly termed "jeep trails."
4W334 "Hole in the Rock" at 3.1 miles - what a great trail! It's often a feature of the Northwest Overland Rally, and is a trail I'd take a good, near-stock vehicle over. Good all-terrain tires are important. It's skinny through the trees! Consider folding in your mirrors. Don't even contemplate taking a full-size rig through this trail. Toyota Tacoma is tight, H3 is tight, Jeep JK is tight. A limited slip or locking rear diff helps but isn't essential, especially on vehicles with a good traction control system. Rated as "more difficult" by NWJeepn.
4W326 "Ball Ridge Trail" at only 2.1 miles is one I'd also happily take a good stock rig with good tires over. Four-low is a must! This is a "reasonable" trail with some steep climbs and descents but no crazy climbs or obstacles. Much of it is heavily forested. Rated as "more difficult" by NWJeepn.
4W315 "Nealy Creek Trail" is only 2.3 miles long, and starts out so easy and nice... Then it gets steeper and more challenging. When we ran it, Josh and I had to ease our Jeeps over a very sharp dropoff/ledge. I haven't done the trail in a couple of years and things change. It was challenging, and a tad hair-raising at that one point. Not recommended for low clearance vehicles. Rated as "more difficult" by NWJeepn.
4W324 "Guard Station Trail" is about 3.8 miles but can take over an hour to travel. It starts out close to Hwy 97, and climbs, climbs, and climbs some more. A fuel injected motor and low gears are highly recommended as is a bit of additional ground clearance. This one is STEEP as well as loose, rutted, tight, and challenging. Absolutely not recommended for a full size rig, or for most stock 4x4 vehicles. Rated as "most difficult" by NWJeepn.
This is a short sampling of the many routes available in the Liberty area. There are many more routes available. These trails are not to be feared, but do need to be respected. The "more" challenging routes are plenty for most people. Enough steep and loose terrain to challenge most of us and our vehicles, but fun, and not likely to damage the vehicle, or lead to injury. The "most difficult" routes are beyond the capabilities of most 4x4 vehicles unless somewhat modified with a bit of a suspension lift, larger heavy-duty tires, and set up with traction control, a tight limited-slip rear diff or a rear locker.
The trails are at their best after a modest rain. After a heavy rain they're nearly impassable unless you really like using your winch. As they dry more and more, they get very "sketchy" with the loose dusty surface again becoming a traction problem. Airing down significantly helps. I normally set the 33" tires on my JK at 10 - 15 psi for these routes.
These routes could be done on a day-trip, or an overnight trip, or could be incorporated into a running of the WABDR or other overlanding route.
I'd highly recommend going with someone familiar with the area and the routes rather than blindly tackling them on your own initially.