It would be interesting to see why ACA chose such an inland routing. I have a strong feeling it's because they wanted to avoid the Astoria-Megler Bridge across the Columbia, which is daunting for some (and would probably lead to complaints at ACA.) The ACA route uses the Westport Ferry instead, which is cool, but that section of US 30 from Westport west to Astoria is busy and can be hairy.
I bet you are right about that. There is no perfect route there, but that is often the case. Personally what I really like to see on maps, is a lot of options. I think it'd be nice if ACA had all of these route options on the maps (though obviously there are limitations). Like the Kirkendall and Spring they could easily have a Coastal Route and and Inland Route. Something I hope they consider for the next edition (and hey ACA I'm available to help with WA routing - there are some better options than K/S have as well )