TXBill is right, there is no way you will get 35mpg, even on the road at 70MPH. I would plan on about 28 or 29 and you might do a little better.

To answer the question TXBill brought up. There are many people that will measure their fuel mileage based on one best case tank of fuel. On THAT tank, they might not have gotten the tank topped off, but on the previous tank it was COMPLETELY topped off.

I keep log books in the glove box of all my cars. I log date, mileage, gallons, and mpg at EVERY fuel stop plus oil changes, service, etc. mixed in chronologically. I see about 10% variation in fuel mileage tank to tank even when I'm doing exactly the same type of driving, then larger variations on long trips vs. much city driving.

Have a great day,