The reader of travel writing, like the traveler, knows that you can't always take people's accounts at face value. The art of enjoying this is learning to read between the lines--between "went three leagues and found good pasture" to find the drama. The pertinent emotional information is not handed to you on a platter as in a novel, but it's in there. You can especially tell they're getting pissy with each other toward the end of the journey, when they had no Native guide to show the way and were forced to start eating the horses.
Humor: the guys cross the Colorado River carrying their clothes on their heads, but lose them in the middle of the ford so they are stuck butt naked on the other side.
Interest: distance a musket ball travels as a unit of measurement
Drama: "detaining" some women, who were out gathering wild seeds, to get them to lead the expedition to the Ute camp. The women were so frightened they couldn't speak. Empathy experiment: you've been grabbed by a group of strange men who don't speak your language. So. terrifying.
So there is plenty interesting reading in here. Still, I got through slow places because I know some of the country and the landmarks, and I don't necessarily recommend this to the casual reader.
This document in translation helped me understand the way that planting colonies, Christianization, and agricultural lifestyle were all bound together in the minds of the padres. Also, the politics the Spaniards waltzed into become obvious: it's clear many Native groups agree to host Spanish missionaries because the Utes believe it offers protection from the Comanches, not because they are so enthused about Christianity or agriculture. It's hard to say what really happened in these Spanish/Native encounters; all you have to go off is this letter the padres wrote to please their superiors. But I still liked imagining.