I just did some of the coastal route - down the Oregon coast from Astoria to Reedsport, then inland to Crater lake. I started with (brand new) 32mm GP 5000 TL tires, but ripped a sidewall before even getting to Astoria (from Seattle), and ended up riding a generic 35mm tubed rear tire purchased in Astoria.It was fine. No noticeable difference between an $80 32mm tubeless tire and a $35 (including tube and install) 35mm no-name tubed tire.
I'll go with another GP 5000 eventually, but it probably doesn't matter so much as the interwebs would have you believe.
Gearing and clothing, now that matters. It's climby, and the weather is variable, to say the least.