Breakfasts: cereals & milk, orange juice (all available from gas stations)
PowerBars of all kind, bananas, Cup Noodles, Pasta Roni, Dairy Queen anything

. Tended to eat at places that were bike-friendly along the way. Anything quick & easy to cook since I often turned up at campgrounds quite late due to sight-seeing
Just got a tin of chili etc plus pack of beer (get a Delta Cargo Net II as they're great for loading hard-to-handle loads) on the rack

before arriving at campground (so not lugging them around), Lays.
1 emergency freeze-dried meal (just in case!)
Gatorade & water for the ride. Beer from the gas stations at night (very cheap & great selections of micros). Powdered Gatorade is very handy where grocery stores are few & far between (it does happen).
The Spring/Kirkendall book often led me (English) to thinking that the "last grocery store..." was the last place to get food from when very often, there would be gas stations with great selections of food, drink etc closer to the destinations.
The Pelican Pub in Pacific City, OR is a place you shouldn't miss. It was a really great sight coming down the hill from the north (check your brakes!). Fantastic views over the ocean & good food. Roadhouse BBQ in Gualala, CA was very friendly the night I was there, back in May. Izzy's Pizza in Newport, WA was a good find with their "all-you-can-eat" buffet. Plenty of choice, even for a picky eater like me!

.... All these places were roadside & not trips off the main route so you will see them & plenty more.
The best thing to do is do you own thing. You may find places others have missed.