It appears that an advocacy group, the Pioneer Restoration Organization, has challenged the conclusions drawn with the mandated Pioneer route study. They prepared a 'Response' to the Amtrak study as provided for by law. Here is a link to their material:
http://www.pioneertrain.com/PioneerResponse.pdf
In essence, other than a routing via Ogden in place of Montpelier, to bring back the Portland Rose, or more specifically the Denver-Portland segment of such, is what the group is proposing. The WB Rose left Denver about 6PM and Cheyenne about 830. It then operated, handling much head-end to every station along the Overland Route to Granger where it diverged on to the Oregon Short Line. This group would have their Rose continue to Roy (just to the East of Ogden) then head South to Salt Lake arriving there 8AM or so. Train then would be wyed and continue on the former route of The Pioneer to Seattle. Boise would be served early afternoon, and the Blue Mountains would be X'd by light of day in both directions. Arrival in Portland would be 7AM and Seattle 12N. EB, the Seattle=Portland departure would be a "Twi-Nite", Boise about Noon, Salt Lake about 8PM, Cheyenne 6AM, Denver 9AM.
That's two days out, volks. That's 421-422, the Eagle/Sunset - minus its numerous and growing on-line population centers.
I guess there are a few potential "mini-Corridors" such as Cheyenne-Denver following the traditional "one a day" pattern of "little town to big town in the morning then back to little town in the evening". I guess, it would add an additional frequency SL-Ogden adding to the existing Frontrunner service. But pity someone traveling from, say, Cheyenne to Ogden; guess what; we throw in an excursion to Salt Lake first.
The advocacy group talks of leisurely travel and offering sightseeing tours for passengers connecting with the Zephyr at Denver. That's great if the operator is American Orient Express (whoops, didn't something happen there?); not so great if we are addressing Federally funded service.
So I think two guesses with the first not counting will show what I think of any such proposal, but others likely hold differing views. Let the discussion continue.