I don't know about "smart" or even authoritative, but Sir Richard Burton (linguist, adventurer, translator of 1001 Nights, discoverer of source of Nile, first white man to go to Mecca, etc., etc.,) also came out to Utah and wrote a book about the Mormons and their settlements. He's smart, writes well, and was certainly a well-seasoned, well-traveled fellow. Anyway, might be worth it for a nineteenth century view.
Joanna