Trying to map out the PP-OO between Grand Junction, CO & Green River, UT

[Route66Fan]

I am trying to map out the section of the "Pikes Peak Ocean to Ocean Highway". Using the 1919 "Official Automobile Blue Book" I tried mapping out the route from East to West, starting in Grand Junction, CO, heading towards Green River, UT, but got lost around Cisco, UT. I then tried mapping out the route from West to East, starting in Green River, UT, heading towards Grand Junction, CO, but ended up with the wrong mileage.
Here is the route from East to West.


Here is the route from West to East (This one had a mistake in the mileage.).


Where could I find a good Grand County, Utah plat map from the 1910's to 1920's?

[Route66Fan]

It seems that the routing of the railroad may have changed at some point.

[Mapmikey]

Here is a 1910 state route map of Utah - https://images.archives.utah.gov/digital/collection/p17010coll68/id/3/rec/2

The chapter on entering the 20th century touches on roads in Grand County - https://digitallibrary.utah.gov/awweb/awarchive?type=download&item=34305

This 1924 map suggests the PP-OO went a different place entirely - https://www.davidrumsey.com/luna/servlet/detail/RUMSEY~8~1~215439~5502412?qvq=w4s%3A%2Fwhen%2F1916%3Bq%3Autah%3Bsort%3Apub_list_no_initialsort%2Cpub_date%2Cpub_list_no%2Cseries_no%3Blc%3ARUMSEY~8~1&mi=2&trs=3

This 1924 map has it split in several places - https://www.davidrumsey.com/luna/servlet/detail/RUMSEY~8~1~201747~3000686:AutoTrails-Map,-Utah,-Colorado,-New?title=Search+Results%3A+List_No+equal+to+%275028.127%27&thumbnailViewUrlKey=link.view.search.url&fullTextSearchChecked=&dateRangeSearchChecked=&showShareIIIFLink=true&helpUrl=https%3A%2F%2Fdoc.lunaimaging.com%2Fdisplay%2FV75D%2FLUNA%2BViewer%23LUNAViewer-LUNAViewer&showTip=false&showTipAdvancedSearch=false&advancedSearchUrl=https%3A%2F%2Fdoc.lunaimaging.com%2Fdisplay%2FV75D%2FSearching%23Searching-Searching

[Route66Fan]

Here is a 1910 state route map of Utah - https://images.archives.utah.gov/digital/collection/p17010coll68/id/3/rec/2

The chapter on entering the 20th century touches on roads in Grand County - https://digitallibrary.utah.gov/awweb/awarchive?type=download&item=34305

This 1924 map suggests the PP-OO went a different place entirely - https://www.davidrumsey.com/luna/servlet/detail/RUMSEY~8~1~215439~5502412?qvq=w4s%3A%2Fwhen%2F1916%3Bq%3Autah%3Bsort%3Apub_list_no_initialsort%2Cpub_date%2Cpub_list_no%2Cseries_no%3Blc%3ARUMSEY~8~1&mi=2&trs=3

This 1924 map has it split in several places - https://www.davidrumsey.com/luna/servlet/detail/RUMSEY~8~1~201747~3000686:AutoTrails-Map,-Utah,-Colorado,-New?title=Search+Results%3A+List_No+equal+to+%275028.127%27&thumbnailViewUrlKey=link.view.search.url&fullTextSearchChecked=&dateRangeSearchChecked=&showShareIIIFLink=true&helpUrl=https%3A%2F%2Fdoc.lunaimaging.com%2Fdisplay%2FV75D%2FLUNA%2BViewer%23LUNAViewer-LUNAViewer&showTip=false&showTipAdvancedSearch=false&advancedSearchUrl=https%3A%2F%2Fdoc.lunaimaging.com%2Fdisplay%2FV75D%2FSearching%23Searching-Searching

It looks like the part that I am trying to map out is a later, or alternate routing. It looks like the main routing went through Vernal, UT, Duchesne, UT, Heber, UT & Park City, UT, before entering Salt Lake City, UT. The southern routing was probably an alternate routing & was also referred to as "The Midland Trail". Also, the 1924 map shows that the southern "Midland Trail" routing, between Grand Junction, CO & Cisco, UT, had been shifted southward & rerouted to go through Westwater, UT. Also, the Valley City, UT section between Thompsons, UT & Floy, UT, was bypassed. I am wondering if this route, at one point, went farther South to Moab, UT prior to 1919. The 1919 Official Automobile Blue Book does indicate that this route changed frequently.

[US 89]

Here's a blog post I wrote on some of the early state and US highways in southeastern Utah that may be of interest, though it does not mention the Pikes Peak highway directly:

https://uthighways.blogspot.com/2020/07/southeast-utahs-us-highways.html

Based on this 1927 Rand McNally, we have, from east to west through Utah:

Colorado line near Mack to Thompson Springs - US 50 (Utah 8)
Thompson Springs to Floy via Valley City (possible alternate through Crescent Jct) - US 50 (Utah 8)
Floy to Price - US 50 (Utah 8)
Price to Salina - Utah 10
Salina to Sevier - US 89 (Utah 11)
Sevier to Cove Fort - Utah 13
Cove Fort to Arizona - US 91 (Utah 1)