ndabunka,
Yes,altitude is a real blessing in modern vehicles.In the old days-before EFI-mass air sensors O2 sensors-with a carb jetted for sea level-the mpg and power would just plunge at altitude.
I figured you must have been too early to have heard the "worst news" about the HH. They have kinda been a flop in the market because they just don't live up to the Prius.You'll make payback in about 100,000 miles(especially with the $4 gas staring us in the face), but it isn't the dramatic improvement over its ICE rivals like the Prius vs Corolla.(about 70% better mpg city in "real life" and 40% better hy.)
We drive from sea level to 7000 ft-New Orleans-Flagstaff AZ-fairly frequently-and once we get above 2000 feet(Amarillo)ect improved mpg;above 4000 ft it is worth about 5-10% in high speed driving-70-75 mph.
I drove almost the same trip-NO to Denver-several times in the 60's 70's-and the mpg would just drop off as I gained altitude.
Yes,Toyota does game the EPA tests at least as well-probably better-than most manufacturers- 31 mpg city would have been awfully nice.
f Toyota builds the stretched Prius that I've heard they plan(maybe 185" long like an HH), it would be good for an honest 40 mpg city,and maybe 45mpg hy(if they increase the frontal area about 10% with 4"more length,and maybe 3" more height). The Prius is just a bit too small to use as a family road trip vehicle. The HHs are just about the perfect size for traveling; a modified Prius 4 cyl could fill the bill just about perfectly.You would have to give up ground clearance, but little else.
Thanks,
Charlie