+1 The closest I've come to dying on my bike was going down Leggett Hill towards the coast. A logging truck got behind me. There wasn't room for both of us. I expected him to wait until there was a wide spot to pass. He didn't. He passed me on a blind corner. He got halfway past and a car appeared from the other direction. He pulled back into my lane to avoid the car, forcing me into the ditch. Luckily there was a ditch. I broke two spokes bouncing along in that ditch.

Since then I've made it a habit to pull off the road and wait anytime I could hear a big truck (especially logging trucks) approaching with no room to pass.

As far as the mileage goes, my recommendation is to focus on enjoyment, rather than riding long miles. Ride as far as you like each day, but make sure you're enjoying it. I think it's better to ride 40 miles a day and have fun than to ride 100 miles a day and suffer. If you've never ridden long days, day-after-day-after-day, it's different. Also, the west coast is all ups and downs. With a load, that slows you down.

Oregon and California both have hiker/biker campsites which are cheap. You can get a shower, eat at a table, use flush toilets, and hob-knob with other bike tourers. I wouldn't stealth camp if I were you.

Bicycling the Pacific Coast by Kirkendall/Spring is "the bible" for this route.