Just read the towing section in the Jeep manual, put it into Drive used Cruise control if you wish, that's how it should be 
I suggests to take it out of cruise if it can't maintain the speed by more than 10KPH, and shif down a gear if its constantly changing, I use sport mode in undulation country (when I remember) and sometimes go back to 4th but on long outback roads just leave it in drive with the cruise set and just steer it.
I suggests to take it out of cruise if it can't maintain the speed by more than 10KPH, and shif down a gear if its constantly changing, I use sport mode in undulation country (when I remember) and sometimes go back to 4th but on long outback roads just leave it in drive with the cruise set and just steer it.