Get yourself an 'America the Beautiful' pass at your first National Park. It's about $80, lasts a year and gets you and another person into any NP free.
When you enter a new state, get to your nearest 'Chamber of Commerce' or visitors center and get yourself a free state map. They are very good and show all the small back roads. I did 49 states and 12 Canadian states/Provs and never paid for a map once. They have free coffee too and good local info.