[SentraSE-R]

I think you can do it. My daughter and I drove from Montgomery, AL to Biloxi, MS last December in her Dodge Grand Caravan. She drove down at 80 mph and got 21.45 mpg, using over 12 gal. to drive ~250 miles. I drove back at 62 mph and got 26 mpg, using a little over 9 gal. It worked out to her wasting 31% more gas to save 1 hour out of every 4.

If I were you, I'd drive the first full tank of your trip at 62 mph. I'd run the AC on recycle, max cool, and max fan, alternating with the AC off and max fan. Try to run the AC on downhills and level while coasting, never on uphills or under load. If you can raise your mpg from 13.8 to 20, you can save $175 in gas, enough for the extra day's lodging and meals.

I'd adjust my driving on the next tank to accommodate my goals. If you only get 17 or 18 mpg, then you might have to drop to 55 mph. If you only get 15 or 16 mpg, then you might want to go back to 75 mph and save the extra day's lodging and food. If you only need $150 in gas savings, you might want to speed up to 65 mph.

If you're like me, and always want to go for max mpg, a long road trip is the perfect time to experiment with high speed P&G, NICE-on coasting down hills, 55 mph max speed, etc.

Good luck, and let us know how you do. 13.8 mpg is pretty poor, but you were hauling a load, and going way too fast. You'll easily beat that, but the question is by how much?