rvparky is a great way to find RV parks and rest areas along the way. And rvparkreviews.com is a great way to find user comments about those parks.
I use google maps to check out smaller highways. I use it to find possible routes from point A to point B, then use google street view and/or satellite view to view the size and condition of those highways.
Another feature of google maps is their flyover. When you select directions from point A to point B there will be a small "3D" button beside "Driving directions to ____". Click on that button and you will get a complete fly over from start to finish. You can pause along the way and zoom in for a more detailed local view.
