I'm sure there are hundreds of novels that have to do with the goldrush, but titles aren't leaping into my brain at the moment.
There is a recent HBO miniseries called
Deadwood, which deals with the goldrush days in Deadwood, North Dakota (
http://www.hbo.com/deadwood/). The series was more than a bit controversial because it attempted to show the unvarnished truth about life in towns such as these (You can just about smell the place!). I have to admit that it took me some time to get into the story: First, because just about everyone is scum. Second, because the profanity is truly shocking

, and I'm not really prudish about that sort of thing. After an episode or two, I became engrossed, however. Some of the characters really start to grow on you in surprising ways. My husband and I even started making jokes about the language after awhile, counting how many times in an hour someone said, "c*cks*cker"! The interviews with the screenwriter provided some very interesting (and valid) explanations for the language. The main argument was that profanity was the muleskinners' normal vernacular for getting oxen and, well, mules to pull heavy wagons. Also, these types of towns were so potentially dangerous, it was safer to keep your guard up and the precision of your words down.
The other novel that comes to mind is more highbrow,
Angle of Repose by Wallace Stegner. It's not specifically about a goldrush town, but it gives a very moving portrait of life in America (near where I live) at the time of the goldrush.