My 7 year old and I are driving down to the beach later today, while my wife and daughter are going down earlier with friends. 120miles, light traffic, flat

I expect 43mpg.
His quote last night: "Dad, now we can have lots of fun and get your gas number really high, since Mommy won't be there complaining."
This was right after he scolded me for using the gas mower earlier instead of the cordless- he didn't want to hear about too-high grass or anything like that.
...hypermiler in training..