I like the Michelin atlas of North America. It is tiled, with all pages at the same scale, rather than organized state by state, with scale changing willy nilly depending on how each state fits on a page or two. But that just may be my prejudice as a GIS and computer mapping system developer, in one of my careers.
For the RV, I also use the Rand McNally MCRA so that I know which highways are designated for large/commercial vehicles, and where the clearance exceptions on those designated roads.
I also use the tourist maps put out annually by each state's highway department, as these usually include highways left off commercial maps and atlases, and often include a lot of POI and legal information.