One of our groomsmen lives just outside of Denver, so we made it a point to visit him. He took us out to Estes Park, where the highest continuously-paved road is located (as well as the hotel they shot The Shining in, but that's for another time).
I would've been satisfied on the drive alone. The mountains were our backdrop for the entire drive over. We drove through canyons with rivers and waterfalls. I was worried my camera would run out of battery before we even made it to the park.