I don't consider James Michener to be a "guilty pleasure", but I acknowledge that not everybody is a fan. I think historical fiction must be an extremely difficult genre to pull off, because on one hand you need to stay true to the basic framework of history, but you need to take enough liberties to develop interesting and engaging characters who draw the reader into actually caring about what's going on. I think I read a fair amount of History, and I've never encountered an author who does this better than Michener.
I have been to Texas a few times, but never lived there. My impressions of the state are largely stereotypical, and not all positive. The brashness and machismo that come across in Hollywood depictions have some truth to them, which can be off-putting, but there is also no doubt that it is a place rich in history. This text begins in the 1500's, when Mexico was a colony of Spain, and Texas was an unexplored buffer zone between Spanish Mexico and "Indian country". It follows through the period of Mexican independence, exploring the assorted social, monetary, and military challenges Mexico faced in keeping Texas in its fold. Texas became an independent republic, and sought immigrants from the newly-formed United States, as well as thousands of direct accessions from various European states in the early 1800's -Scotland, Ireland, and Germany in particular.
This is an area where Michener is underrated as a scholar. This portion of the book includes a masterful dissection of the many ways which the newer (Protestant, rural, individualistic, agricultural) residents contrasted and often conflicted with the older (Catholic, urban, community-oriented, artisan) Texans- and how this mixing formed the essential character of Texas which continues today.
Later chapters include the Alamo, Texas' entry into the US (the main issue which James Polk ran on for President), slavery and the Civil War, the Indian Wars (up through the 1880s), the later waves of immigration, the discovery of big Texas oilfields, and into the 1980's when the semiconductor industry started to pull the economy out of the OPEC-induced "oil shock" of the 1970s, and state politics faced contentious issues of water management.
At 1300+ pages, this book is a bit of a time investment, but the reading is not difficult, and my feeling is the payoff is well worth it; I honestly feel this book has enhanced my overall sense of American history. (i.e. the timeline, the important issues of the day, and the realities driving large-scale trends.) To my mind, Texas uphold's Michener's well-deserved reputation as one of the best (perhaps the very best) authors of single-volume historical fiction, ever.