How about "trivia", make a game out of license plates, how many out of state, have them learn to read a map by following the road, how many miles to next exit. Exit numbers are on the road maps. Good way to learn directions, north, south, east, west. By looking at the "mile marker signs", how long does it take between signs. 60 miles per hour would be one mile in a minute. Great learning tools with a little fun. Name something historical about some of the towns / cities, what is the Capital, what is the town known for, major industry or sports team?
So many people with GPS really don't have a clue "where" they are or where they are going geographically.
Who can spot the first wild animal, deer, rabbit, squirrel, antelope, etc.
Look at farms, who can spot the first horse, cow, wind farms, water towers, cloud formations, jet streams, the first mountain top.
Check out roadside markets, fruit and vegetable stands are popular in summer, rural areas.