Turns out the refusal of Wyoming to rearrange US 30-N and 30-S at the request of Utah, in lieu of US 30-C (see https://www.aaroads.com/forum/index.php?topic=25338.0) didn't end the desire to get a central US route between Tremonton and Sage.
Wyoming officially applied for US 330 for this route in Oct 1954. See pg. 35 of the 6th pdf at https://drive.google.com/drive/folders/1KPB9uJUfDzn0_G_1_Taba1OVgjuuvI7T
Saw no further reference to this through the end of 1959...