I live in western colorado and tow with an '08 Sequoia, same engine as you.... I use my cruise control on the highway, not in the mountains it downshifts a little late and then goes down two gears instead of just one.... I don't use two mode that much, I feel I get worse gas mileage as it keeps the engine at a higher rpm for longer than it needs to...
I do get better gas mileage when in cruise!!! about .5-1 mpg better. If the head wind is really strong. like my trip to ZION i keep it out of cruise, easier on the gas mileage, as it tends to downshift two much...
May you have at least one sunny day, and a soft chair to sit in..
2008 5.7 L V8 Sequoia
AIR # 31243
WBCCI # 6987
FOUR CORNERS UNIT