Utah's First European Visitor?

In 1920, almost 100 years ago, Herbert Bolton published his textbook on the Colonization of North America.  Bolton, and his co-author, Thomas Marshall, explained that their purpose was to correct what they saw as an over-emphasis on the explorations of British settlers from the east coast, and to include the stories of Spanish, French, and Russians as well.  That being the intent, the book starts, as it must, with the Spanish, because, while Americans like to focus on Meriwether Lewis, the fact is that Lewis and Clark were 300 years behind the Iberians.

Because my interest, as always, is in southern Utah, I took up Bolton to discover the first European visitor to our state.  And I may have found him.  A Spaniard, of course, and a lieutenant of the more famous Coronado.  (Coronado, as we know, made it all the way to Kansas in 1540, a spectacular exploration made in pursuit of the seven cities of gold.  An exploration that also earned him a somewhat snide comment from Bennie DeVoto:  "[T]here was no gold, no silver, no emeralds, no lords of the country lolling in gondolas and soothed asleep by golden bells, no golden plates and ewers.  Quivira was not a new Peru but only Kansas."  But I digress.)  The man's name was Cárdenas, and I expect that he was a Spanish soldier.  Bolton says that he traveled, also in 1540, northwest from the Moqui Pueblos until he reached the Grand Canyon.

To go northwest from the Moqui (which I take to be Hopi) Pueblos means, from a look at the topography, that you have two choices.  First, you could go almost due north along Chinle Wash to its confluence with the San Juan, or you could take a more southwesterly route and follow Moenkopi Wash to the Little Colorado River and its confluence with the Grand Canyon.  According to a map supplied by Bolton (and reproduced above), Cárdenas took the latter route.  While the map is hand drawn and of insufficient detail to know for sure, it appears that Bolton believes that Cárdenas paralleled Marble Canyon from approximately the mouth of the Little Colorado to the mouth of the San Juan and back.  This seems plausible from what I've seen of the country.  With the formidable exception of Navajo Canyon, most of the exploring would have been done on the Kiabito Plateau (barely visible on the eastern side of Marble Canyon in the picture below).

Assuming all of the foregoing to be true, the question remains:  Was Cárdenas the first European to visit what is today the state of Utah?  Did he proceed all the way to the San Juan, passing 37 degrees of latitude (the magic line) on his way?  There is probably no way to know, though I admit that my sources are secondary, not primary.  On the one hand, the visit seems possible, the country was no worse (for traveling) on the Utah side than it was on the Arizona side.  On the other hand, would Cárdenas really have crossed Antelope Creek, Navajo Canyon, and several other obstacles after hundreds of miles of rough travel across the mesa country simply to reach present day Utah?