Considering US 466 was approved years before Hoover Dam was even finished it seemed like a worthy headliner for the blog I did on highway designations over Hoover Dam. I'm fairly certain there isn't much out there on NV 26, NV 42, US 66A and US 93X:
https://www.gribblenation.org/2023/06/legacy-of-us-route-466-part-4-hoover-dam.html
US 466 probably should have been retracted to Barstow when US 93 was extended to Kingman, AZ in 1935. With the Barstow-to-Las Vegas, and the Las-Vegas-to-Kingman segments co-designated with other US routes (US 91 and US 93) was unnecessary duplication in my opinion (I feel the same way about the former US 60/US 70 duplex for most of the length between Los Angeles, CA and Globe, AZ).
Considering how unhappy California was with the prospect of a Barstow-Morro Bay US 466 in 1933 I couldn't see that happening. The whole push for US 64 via giant multiplex spawning US 466 is bizarre.