I have only read one or two Vonnegut novels, and no Burroughs. I will definitely look into both.
As far as McMurtry goes, he doesn't just do Westerns, but he does do great Westerns, and they are his best work. He is a great storyteller and what I like about his novels is that there isn't the froofy romance or romantic notions of what life is. Everyone has flaws, some pertain to the plot, some don't.
Have you ever seen the movies "Hud", "The Last Picture Show" or "Terms of Endearment"? They are all from McMurtry books. I loved the books better than the movies, especially with Terms, as the movie really only takes about the last 50 pages of the books and attempts to tell the whole story with it. Of course there is Lonesome Dove, which won him a Pulitzer, and it can't be equalled. It wasn't equalled by the sequels and prequels he wrote to it.
So, to suggest a first McMurtry: tough! My first one was Sin Killer, but it certainly wasn't his best. His writing style sucked me in, even though the plot seemed rather silly. If you like historical fiction you will love all of them.
http://en.wikipedia.org/wiki/Larry_McMurtryOne of his great methods of storytelling is by using group travel, trekking across unknown or known ground with a group of characters. It makes for witty banter, lots of life/death situations and geography lessons too!
OK enough gushing. Go check out Lonesome Dove (the miniseries was alright, Robert Duval was brilliant, but it was a miniseries, and has the miniseries cheesiness factor) and please let me know how you like it!
P.S. his son James is a talented folk songwriter-singer and guitarist who played for Camp Casey in Crawford! Talent and progressive thinking run in the family!
I certainly plan on investigating your suggestions. Thanks!