Thanks for the welcome!
You’re absolutely right about route numbers – an important detail! Here we go:
Leave Dallas to Amarillo on 287, continuing onto US40 to Albuquerque.
North on 85 (might go to Santa Fe if recommended), up 550 to Aztec, then north on the 170 and 140 through the southeastern part of Colorado.
491 into Utah at Monticello, head north on 191/6 until around Provo, UT, continuing to Salt Lake City on the 15/84
Then continuing on the 84 all the way from the Utah/Idaho border to Boise.