I've been wanting to do this for a long time - the whole 20.6 mile Wilson River Trail. I finally got my chance yesterday. What a great trip! There was a recent thread about this trail that poked around the edges a bit... anyway I thought I'd post a more thorough trip report than I usually do...
First, the State Forest has produced an excellent two-part overview/description/map of the trial. You can fine these pdf's here:
http://www.oregon.gov/ODF/TSF/docs/WilsonRiverEastTrail.pdfhttp://www.oregon.gov/ODF/TSF/docs/WilsonRiverWestTrail.pdfSome photos are below. More photos & descriptions are on my site at:
http://www.phlumf.com/photos/tillamook/index.shtmlI've screen-shotted the trail maps from these below to help describe the trail further. I hope they don't mind.

I started at the Elk Creek Trailhead at 6am. The campground there is closed, so getting to the trailhead from Hwy 6 added about 0.3 miles to the hike (but who's counting?). Forecast was for drippy skies in the AM, but clearing in the PM. It never really cleared-up (or warmed up) however... which was fine by me.

The trail starts off with a steady uphill a few hundred feet, and some fleeting views of the surrounding forest. Eventually it heads down and levels-off as you get close to the King's Mtn. Trailhead. I think a lot more people have hiked this bit, so it'll probably be more familiar.
I was hoping to see some elk in the early morning. I saw plenty of sign (prints & poop), but no elk. The moody forest was nice to look at though
From the King's Mtn trailhead, the trail rises more steadily, topping-out around 2000ft or so near little kings mtn. btw, this is a great alternate route up Kings mountain. It does involve a bit of bushwhacking to connect back to the King's Mtn trail (heading over little Kings Mtn), but it makes a good loop, and the Wilson River Trail is generally in better shape than King's Mtn.
From here, the trail contours around the headwaters of Lester Creek. I was impressed by this section. You're away from the road, so there's no road noise, plus there are a series of steep cliffs which are great for views.

And tiny little flowers...

From there, the trail descends through a carpet of Oxalis and Stream Violet to a massive and beautiful bridge over the North Fork Wilson River. Considering this bridge is for hikers and bikes only, it seems a bit overbuilt, but it's really nice.

The trail then follows the river for a bit, and cuts away just before this multi-tiered waterfall of Lester Creek spilling into the NF Wilson. This waterfall was especially pretty, but is on private land. (Not a bad backyard, eh?). plus, it's across the NF Wilson, so it's hard to get views of the whole thing.

Next, the trail climbs quite a bit - maybe 400ft - to get above North Fork Road, before eventually descending to the Jones Creek Trailhead. This wasn't the most inspiring bit, but it was still nice to hike through.
Next map shows the west part of the trail

Soon afterward, the trail comes to the Tillamook Forest Center, which has an even more massive hiker bridge. The Forest Center is really impressive, and worth a visit on its own. A steady stream of 50-something couples wandered out as I ate my lunch. There are vending machines there, and right when I pressed the button for a Dr. Pepper, I realized I could have had a 20oz hot coccoa instead. Dumb dumb dumb dumb! So, I shivered down my cold high-fructose corn syrup, and headed off again.
Right after the bridge, there's a clump of Fawn Lily that I'd photographed a couple weeks ago. There were just a couple left blooming.
I then passed all the people I saw on the trail all day. A mom with 2 kids, and 2 guys on bikes. That's it. Millions of people living in Portland and that's it?
Now, how appropriate was this? Right on the Wilson River, a Wilson's Warbler. He was hiding really well in the thick brambles, but I waited patiently and managed to snap some good shots.

The trail rose a couple hundred feet and quickly passed by Wilson Falls. Then, more rambling through the forest. The Oxalis was just going off - about as thick as I've ever seen.

Just after the Bridge Creek trailhead, there's a stream with a pretty decent-sized waterfall about a quarter-mile upstream. It'd require a short bushwhack, but is quite accessible... another place to come back to.
The trail then descended to what was the prettiest side-creek along the way - Wolf Creek. This creek was all mossy boulders, catch pools, mini cascades... I could spend a whole day wandering up this creek photographing stuff.

from there, the trail climbs about 800ft to contour around the headwaters of Ryan Creek. The geology in this area was noticeably different. I think the underlying rock was much harder... this is probably what makes Wolf Creek so nice (it's not as susceptible to erosion). The side streams in this area mostly fell down near-vertical rock faces. There were some slides along the trail here, and a couple blow-downs, but nothing too bad.
After crossing Cedar Butte Road, the trail descends through a "thinned" forest. The trail was a bit overgrown with grass, and kind of lumpy. By this time I was pretty beat... which helped make this part challenging... but at least it was downhill.
I eventually reached Hwy 6 - the conveyor belt that'd take me 10 miles back to my car. All I had to do was push the button with my thumb. It took about 45 minutes, but I got a ride from a nice guy & his little boy. It's always a little depressing to be passed by dozens of mostly-empty cars, when I have a sign reading "10 miles", look (I think) pretty nonthreatening and dorky, and obviously just a hiker... But, then, with so few people on this trail, I guess nobody knows it's there. Oh well, I did get a ride before dark, so I guess that's all that matters.
It ended up taking me 12 hours. But about 2-3 of those were on the account of my obsessive picture taking. (It's hard to make progress when you're sitting in a bush waiting for a warbler to come back to his perch). I hope more people are able to get out there & enjoy this under-used treasure! Happy Trails!