Once upon a time I thought you could get xtra copies of the Milepost map, "I think" means I may not be remembering correctly. Buttttttt, who puts out a good overview planning map. The MP map has it a...
If you have GPS, do not be surprised if it is wacky during your trip north. Near Grand Prairie, our GPS kept telling us to make a u-turn and then turn left thus putting us exactly the same course (of course we ignored it) and once even displayed "go that away." Other's we talked to had the same problem. Also review how you add Lat/long coordinates into your GPS because many campgrounds do not have traditional addresses. The Church campground book did list Lat/long and address if available.