Interesting comparison for sure. Sounds like something my family would do when we are all headed out together. Sounds like the Ecodiesel may well be the mpg winner hands down.
I also think the mileage on the downhill portion sounds a little bit off for the EB, but ... a lot of people also report much worse unloaded mpg than I seem to get with my EB, so who knows.
My own anecdote: A couple trips ago, we set out to camp at 10,600 elevation, so a gain of a little better than 6500 ft elevation over about 80 miles from our house, w/ about 30 miles of interstate and the rest 2-lane state highway with some quite steep (up to 10%) inclines. Yes, a few ups and downs headed each direction, but obviously mostly up hill one way and down hill the other.
After parking and getting set up at the campground, which is literally at the top of the mountain, the dash gauge on my F150 was showing about 7.8 mpg, if I recall correctly. I did not reset, but when we got back home it was showing 11.3 mpg over the roughly 160 miles, which I verified with a hand calculation when I filled up. So it definitely did a lot better on the way back down!
