There were some muddy areas on the trail/road but only in the first mile.
The sunshine lasted until about Trestle #8 when a blanket of gray gloom covered the sky. With the sky out of commission, I turned my attention to stuff along the trail like colorful lichen,
wet rock,
and the junk car (almost like one of Don's hikes off Palmer Mill Road
) just before Trestle #6.
By the time Trestle #4 took me across a pretty energetic Swale Creek,
the sun was starting to crawl out from behind the gray gloom,
and I could once again see my feet.
About 6.5 mi in, you come to a wide spot shown on some maps as "Swale" - possibly a siding, maintenance area, or watering stop on the old Lyle to Goldendale railroad.
I'd come down to "Swale" from Harms Rd on a previous hike, so this was my turn-around point. Thus, after a short lunch, I headed back - in pretty much full sunshine! Even had to take off a layer!
With the sun shining to bring out the colors, this becomes a very visual canyon. 
Just before reaching the TH, I looked back and saw that the moon was still up.
The warm and sunny second half of the hike redeemed the gray and gloomy first half, making for a really nice day on the trail. No flowers yet - lots of Stellar jays and squirrels, one scree of a Red-tailed hawk, and a grumpy Bald eagle in a tree. No people. 13.5 mi, 600' EG.
