I parked my car at 1880m (6200') elevation on a road spur shown on the USGS 7.5 min (metric) map 900m ESE of the usual Shepherd Pass parking at Symmes Creek. That put me close to both Shepherd Creek and the Symmes Creek trail head. On the map it is about two miles up Shepherd Creek to the Wil Ck branch off and about 2 1/2 more to the 9700' level which is Secor's recommended start point for the E Horn via Wil Ck route in his High Sierra guide. There is a little fisherman or hunter trail from the road end, but it didn't last long. I then had to traverse in the loose gravel and sand because the vegetation in the narrow creek bed was too thick. The first half mile in the gorge was the most difficult. Then there was an animal trail that made the going easier through the aspens and brush. Higher up the going was still easier as the vegetation thinned out and the canyon was wider.
I camped at 2900m (9500') at the upper edge of a recently burned area. Fortunately a lot of brush had been cleared by the flames, but some of the 400 year old jeffrey pines were killed too. Starting at 2pm after getting a permit in Lone Pine, it took me 5 hours from the car to where I camped. I had 16 lb on my back - light bag, bivy sack, no stove. There was plenty of firewood there at my camp, and I enjoyed making one at sitting by it. Probably better for the ecology, burning the wood, so the downed wood won't fuel another fire. Remnants of an old camp were there - rusted cans and bottles; perhaps an old prospector's camp, or maybe used by Norman Clyde.
Next morn I went up to 3040m elevation where there is a major drainage and I could study the route for a while, and finally made up my mind to give it a go up the E horn, via the class 3-4 route described in Secor's book. Went up as described to the red loose rock and continued up to the right hand drainage which ends at about 3700m and becomes the easy broad summit slope on the E Horn's NE side. On the route I found only 3 exposed spots, only about 10' each: class 3+ to 4-. The rest was mostly class 2, with some 3. Six hours up the 4600' to the summit (14,125'); some time lost going up one wrong ridge. I had my full pack with me. From the summit an amazing view! At least 50 miles of the Owens Valley lay beneath; Lone Pine and Independence 10,000' below. Since I was alone, I enjoyed talking to various people in all directions as far as Las Vegas on my ham radio for quite a while. Weather was perfect. Warm, in T-shirt and shorts with no wind.
There was a register inside a glass bottle. I was surprised to see only 5 parties having signed the register since October 1979! The party that left the register did not put a date. Shortly I realized why there so few. I began looking for a way over to the W Horn, only 200m distant. Although it is rated class 3-4 in Secor, I could not find a way that I was willing to attempt. Too exposed and loose! Also, there was ice in the notch between the summits. Just W of the summit there is a second notch with vertical sides that I couldn't get to unless I had a rappel rope. The route 500' below on the S side looked difficult in the steep snow there. One doesn't simply walk over the other horn as implied in the directions. It might be easier from W to E as one ascends the most exposed part rather than descend. Anyway, almost nobody has done it that way either (at least since 1979) per the register. Another factor is the bighorn sheep closure starting July 15, needing an average snow year or less to avoid snow on the rock routes.
So, the only way onward was back down. I was able to return to a higher level on Wil Ck by veering W at about the 3800m level above a peaklet and then through two other drainages. I carried an ice ax (but no crampons), and it was useful across some snow banks. I camped at the 3370m level on the bottom. Down by this route there was nothing higher than low class 3; mostly class 2.
The next morning I went through the Wil Bowl and up the standard Bolton Brown (="BB") (class 3) route. I went across the triangular 20 acre, 14,000' high plateau and traversed around to the notch between the W horn and the plateau's NE end. I didn't need to drop down 150' as indicated in the guide. Then from that notch a 4' wide notch is about 60' up to the N. >From there the route to the summit is seen - about 100' down to the NNE, 80' across a ledge to the NE, 120' up a chute to the NE to a ridge, 40' up to a mantle ledge, about 30' up a slot-chimney, up over or around a large block, and then another 100' of class 2-3 wandering NE to the summit. This route to the summit of the W horn (14,160+) is no higher than class 3; it's easier than the class 3 on the BB route. The hardest part was the 6' high mantle. I could find no register on this summit, however. I should bring one next time I'm exploring peaks. I went back to the plateau via its peaklet just W of the horn by going 200' on a ledge SE of the notch and up 3rd class slabs to the peaklet.
Next I went to the 14,375' main Wil summit. Many had signed the register, and there was plenty space for more. I didn't want to camp another night since I had no dinner and didn't feel like going to sleep hungry. So I went all the way back that evening via the BB Route through Wil basin and Shepherd Pass. Then down the Shepherd Pass trail, boring, with 550' extra up and down, and excessively switchbacked (I hate level switchbacks), arriving back at my car at 10 pm. I enjoyed a good sleep there at my car after an enjoyable climb.
Tom Kenney adds:
Included in the book "Climbing California's 14'ers" is a remarkable story by Warren Harding of his winter ascent of Williamson by this route. It's hard to glean any useful details from Harding's stories, but he gives a pretty good impression of what to expect on this 'interresting' route...
Looking forward to trying it myself someday.