As you go east on I84, you have several options for turning south:
OR35 at Hood River climbs gradually pass orchards and then forest, meeting US26 on the SE flank of Mt Hood. Just a bit west of that junction is the turn off to Timberline Lodge, well up on Mt Hood. US26 then drops gradually to the Deschutes River and US97.
At The Dalles, I84 enters the dry side of Oregon. US197 runs south to US97. It has a drop and climb a Maupin.
US97 is further along, and has a gradual climb to uplands of central Oregon.
One way or other you have to climb from sealevel along the Gorge to 5000' around Bend (and points south). But for the most part the climbs are gradual.
