I wrote about this one on the blog around 5 years ago, but I figure you might have forgotten (heh heh). Sure, it's a western, but it's by Evan Hunter. I was in a thrift store the other day, saw a copy of the paperback, and picked it up. I figure you can never have too many copies of Evan Hunter books.
The Chisholms appeared in hardcover in 1979, and it was the basis for a TV mini-series that year, screenplay by Hunter. (Maybe you recognize Robert Preston there on the book's cover as the Chisholm patriarch.) The mini-series led to a short-lived TV series (13 episodes) in 1980. The book is a family saga and "way west" epic. It has a little bit of everything, and it's all good. The Chisholm family leaves Virginia to travel to Oregon and make a new start. Here's what I had to say in the original review: "They leave at the wrong time of year and so have to travel virtually alone rather than with a wagon train. They run into scamsters [crime element!], Indians, bad weather, and plenty of other problems."
As far as I know, Hunter never wrote another book like this one. It's quite a change of pace from his crime novels, and I recommend it highly if you're looking for something a little different.