Portland to Hood River

Apologies if this has been covered recently. I’m looking to do a light tour on the Old Columbia River Highway (primarily) from Portland to Hood River. I can’t sort out what happens at Viento State Park. Do I dump onto I-84 and white knuckle for 10 miles or so? Is that legal? Certifiably crazy?
I’ve done the section from The Mosier tunnels to The Dalles a couple years ago; fabulous :). I’m a Seattle person so am not as familiar with the Gorge as I’d like to be :). Appreciate your input and help!

It is legal to ride on I-84 outside of Portland. I don’t know if I’m crazy, but I and others have done it multiple times. For now, you can do all but 5 miles on the Old Columbia River Highway.

Riding on I-84 isn’t as crazy as it sounds. Cycle Oregon has routed 2000 cyclists down the freeway shoulder in years past. The shoulder is wide and the road noise deafening. I’ve ridden on I-5 between Portland and Roseburg multiple times and it was ok, not great but ok.