With 4.30 gearing, I run my Aisin in 6th gear most of time at 60-65 mph without gear hunting. This is somewhere around 1700-1900 engine RPM. Most moderate hills do not trigger a downshift and the steepest passes are carried in 4th. Typically my GCW is 21-23k lbs while carrying a truck camper that is 12.5' tall with my enclosed trailer in tow.
I don't run my truck faster or empty very often, so this works well for me with use of all gears. Average distance per year while loaded is around 10 k miles, so the truck gets plenty of camping.
