Help information o on I84 through Columbia River Gorge

Leave it to an Arizonan to quibble about the name! :) It is wide, carrying a large river, two highways and two railways. But there some significant heights as well. Multnomah Falls are 600+ ft. Beacon rock is 800 ft high. Vista Pt on Crown Pt is 700 ft above the river, and Hwy 14 rounds Cape Horn at a comparable height. And the Wiki page claims the Gorge is 4000 ft deep, though I don't know where that's measured from. The highest point in the area is Mt Hood at 11,000 ft.