[Redram99]

I find the tow haul mode annoying when towing as it seems to hold lower gears to long(sticks in 4th way too much). Personally I use the seq shift option and only allow the tranny to shift up to 5th unless coming down a slight grade(then I let it use 6th). Then I can also use the engines compression braking ability on steep inclines and before corners.

For climbing hills, the trans will find the right gear and hold it... typically, but there are exceptions to every situation.
Also, I don't use cruise when pulling a trailer. I find it very hard on fuel when I do. You can do a much better job at fuel management by using your right foot. You can also keep the tranny from hunting on hills by using the pedal. I find that with cruise control if you are entering a slight grade the CC allows the speed to drop too much before applying throttle which causes the tranny to shift from 5th to 3rd and will hold 3rd all the way up the incline whereas by using my foot I can anticipate the grade and keep the tranny in 4th and maintain speed.
Just my 0.02