Great ride report! I was out there as well, on the one-day ride. Probably saw you. Worst part of the day was definitely Hwy 30, with 93F heat coming down --- and radiating up from the pavement. I was really grateful for the older couple in Scappoose who'd set up a mini water station and let me soak myself from head to foot in their hose. And the tailwind was sure a welcome relief.
Not sure I could have stayed hydrated this year without Hammer Nutrition products: liquid fuel mix of HEED and protein powder (non-soy version of their Perpetuem), about one bottle per hour (even more down Hwy 30), plus so many Endurolytes electrolyte capsules I lost count. Also experimented this year with some of their other anti-fatigue supplements, and felt surprisingly not as bad down the stretch as I would have expected, given the conditions.