The Grand Columbian iron-distance course has 5700 feet of climbing, according to Google. I have a disc wheel cover on my rear wheel right now, which adds 500 grams of weight. Should I keep it on there for the race, or take it off? What about swapping in a real disc?
The GC course is demarcated by two key features – the initial climb onto the plateau and then the run up “Baghdad Road”; the rest is rolling. The disc will not hurt you too much on the climb, but if it is windy on the plateau or running cross up BR then it will present a challenge unless you are a very strong cyclist or have some weight to you. I’d make a wheel decision the night before depending on the weather outlook. I’ll likely run the 404s. Having raced there the past two years I would say we don’t see may discs, more aero fairings.
you might consider a shock absorber, since the bike course is like the cobblestones in paris-rabuoix. watch for the fresh oil and gravel spots also, and the unmarked speed bumps over the dam.