Field Notes - National Highway Map
Why not get a FN Highway Map to go with your set of Mile Marker notebooks? It's an old school map that once you've unfolded will take you half an hour and lots of choice words to fold it back properly.
One side shows the continental Interstate system, the other is packed with information. It includes a history of the Interstate System, CB radio glossary, mile marker and exit numbering conventions, traffic control sign design guidelines, a license plate game scorecard (get one in the basket now, an essential to any long journey). There's plenty of other stuff to keep you all entertained on your next adventure in the car.
3.5" x 8" map which unfolds to 36" x 24" - good luck refolding it!