Rugged Individualism in the novel Lonesome Dove by Larry McMurtry?

I think the characters' self reliance is a major theme of the book.  They kind of operate outside of the boundaries that we think of as society.  The setting is in the untamed west where there is no one around to enforce laws so there really are none.  They do not have the help of the government or the law even though they are former rangers.  Its kind of a state of nature type situation.  Anyway those are just some thoughts i rattled off.  Its a good book I hope this helped a little or at least got you started brainstorming.