Taking off tomorrow with a goal of a 70mpg tank somewhere along the trip. Grabbed the elevation profiles from Google Earth for my route 'to' and the route 'from' St. Louis. Decided to take Hwy 50 to Interstate 70 to get there (wanted to go through Colorado once) and then will probably take Interstate 80 to come back home.
Hwy 50 / Interstate 70 elevation profile:
Interstate 80 elevation profile:
I'm thinking that my best chance to get a 70mpg tank is going to be on the last day of driving 'to' St. Louis.