Can anyone recommend any not-to-miss sights on a road trip between portland and denver?

You need to get out of your car and hike in the Central Mountains. Eagles Nest Wilderness Area and Holy Cross Wilderness Area cover many of the summits I climb, although you can also spend weeks hiking the Fourteeners and high passes along the Continental Divide. At the very least, hike up Grays and Torreys, Elbert or Massive, Bierstadt or Evans.