Ronin - I've backpacked in the Lost Creek Wilderness Area several times. The trails are excellent and not overly challenging. Lots of interesting places to camp. Very easy to hike a long loop and make it a multi-day trip. Nat Geo Topo map 105 covers the area well and you can find it at REI, Barnes & Noble, etc. The trickiest part is driving to the trail heads - I've used Goose Creek Trailhead, Spruce Grove Campground, and Twin Eagles Campground as entry points. You do not have to use the campgrounds - in fact there are no "official" campgrounds inside the Wilderness. The area around the abandoned shafthouse is good spot to camp and pretty popular.
These websites may be useful for you -
http://dualpineclub.org/news/backpac...ek-wilderness/
http://www.summitpost.org/lost-creek-wilderness/178676
I always call the Forest Service Ranger district before I head out to check on any fire restrictions or other issues.