Sorry pax, but just a second opinion from a former CO resident:
The Rockies are still there and scenic as ever.
HOWEVER Friends don't let friends drive I-25 or I-70 through Colorado.
Particularly anywhere within 100 miles of Denver.
(Have a good trip to Yellowstone anyway, gub.)
I am also an ex. 55 year Denverite. I am doing a quick in and out next Wednesday-Thursday, around Arvada/Westy area. The traffic is horrendous anymore. 22 hour a day rush hour on I-25, I-70 and, of course, I-225. They actually only built that (I-225) as 2 lanes to begin with and as soon as they opened it up to traffic, they started to work on expanding. Great foresight!