We took Miss Purdy (1984 auto) on an early fall trip to Pagosa Springs last year and the over all mpg average was about 18 - 19. On the open road and traveling around 85 mph (right in amongst a large herd of 18 wheelers) I was getting over 20 mpg. Once in northern New Mexico and Colorado on the twisty mountain roads the mileage dropped to 15 - 16. I used the typical flat-lander steep mountain driving technique - Accelerator applied heavily up the grades, brake pedal heavily applied down the grades. Some of the sharp curves out around the smaller Colorado towns and communities had no guard rails.
There was one 100 mile section of interstate out across the Texas pan handle that we did good to get 5 mpg while almost being pushed backwards by a 90 mph head wind. The funny part was that I had plans to turn the key off during the return trip over this same section of road and just coast home to Dallas. But while driving back we had a head wind from the opposite direction.... I should have known you can't out smart the West Texas weather patterns
We all enjoyed every minute of the trip - including Miss Purdy.
Michael