Well-organized marathon, with detailed descriptions and instructions on their website. Fabulous people (crew, volunteers, and spectators). Ideal course profile - I got 18 minute PR and BQ-ed by almost 6 minutes.
If you're lucky (like us in 2016), you'll get a perfect weather and amazing scenery as bonus.
Remember to turn off Auto-Pause on your GPS (I didn't), trees and mountains block the signal and that pauses the watch.
Train your legs for long (but gradual) downhills. Get used to running on gravels.
The tunnel was fun! The surface in the tunnel was a bit uneven, but wasn't really too much of an issue.
The rail to trail conversion kept a nice 1.5% downhill grade for the last 23 miles. Made it easy on the quads compared to other downhill courses.
Running on the north side of the mountain made the GPS not work well. I had to rely on manual mile marker splits and heart rate to maintain my target pace.
The aid stations for the last 10k seemed to be farther apart than other marathons.
I'm doing it again this year. ;)
The last 10k had leaves on the trail, which could be slippery, but it wasn't too much of an issue.
Good food just down the road in Issaquah.
By SE about 2015
The weather was great! Low 50s with a hint of mist here and there. Kept us nice and cool. The tunnel was a hair foggy and cold which created for even more visibility issues, but it only lasts 2.25 miles. Hard to complain really when you take 3 minutes off your PR and qualify! I will be doing this one again
I bombed my way down the first half when I knew it was more downhill. I knew I would come back down to Earth eventually pace wise, but it worked for me. The trail is more compact dirt with rocks. I had shoes on that weren't too cushy and pretty light and they worked well for me. The scenery is gorgeous. A few pretty high bridges on the course, but if you are afraid of heights, just crank up the pace
We stayed at the Roaring River B&B. They were great there! About 12 minutes from the drop off point for the buses. Owners were great, walked out to a view of the river, really hard to complain about that