Check out Adventure cycling. They have all kinds of information for bicycle touring, including maps to get you across the country and off the main motor routes. There are also journals, equipment lists and good info.
The web site is www.adventurecycling.org
I think you'll find most people are helpful, and from what I've read there are places that the drivers are kind and courteous and there are places where they are not. It might help to call them and I'm sure they can give you the heads up on a lot of these issues.