The City of Everywhere was memorable but actually was not in service very long. I believe it was launched on December 7, 1969 (an inauspicious date). The UP schedule that I referred to was in the January 1969 Official Guide, with an effective date of October 27, 1968. In that configuration, the City of Portland and City of Denver were combined between Chicago and North Platte. At North Platte the trains split. BTW, in this period the Cities of Portland and Denver covered a number of small towns between Omaha and Cheyenne after discontinuance of the mail train that had served them.
For the period that we're focused on the combined City of Portland and City of Denver running with the train numbers of the Portland train was just a deviation through Denver by the Portland train. From what I have on hand, the deviation ended effective October 29, 1967.
Now, for summers 1965, 66 and 67 ---
In all three of those summers the Domeliner City of Portland departed Chicago Union Station at 3:00 p.m. and arrived in Rock Springs at 2:37 p.m. via Denver. In the summer it carried a Buffet-Lounge for cafeteria service in addition to the usual dome cars and flat-top cars.
The deviation accomplished a couple of things. As UP advertisements proclaimed, the City of Denver (which really was the Portland train) now had the ONLY dome diner between Denver and Chicago. The Q was eating their lunch with two daily CHI<>DEN dome trains (California Zephyr and Denver Zephyr). Secondly, traffic between Denver and the Northwest was remaining strong and with the Portland Rose this gave them 2x daily departures on that route.
An interesting side effect of the deviation is that westbound the Portland train was lapped by the California train. When the New York Times circulation experts planning the Western Edition visited Portland they checked into the Multnomah Hotel on a Tuesday afternoon and found the Sunday New York Herald-Tribune on sale. When would the Sunday Times be delivered? Midday Thursday! The H-T left Penn Station on a Saturday night and got to Chicago along with the Times on Sunday afternoon. The H-T bundles were loaded right away onto the California train to Green River. At that Wyoming metropolis they were put onto the lapped Portland streamliner, arriving in the Rose City in time for deliveries before lunch. Meanwhile, the good, gray NYT was plodding along on mail trains and was delivered to sales outlets on Thursday with the regular magazine deliveries.