There is also the balancing of a load. many do not even think about how to pack and vehicle even if not towing. Considering the weight and a distribution of weight can greatly affect all aspects of the drive and safety while driving. As well as also looking at the tire information for max load information.
The last thing is the not so talked about things like changing your spark plugs when you are planning a trip that includes towing a heavy trailer. If you don't have new spark plugs, you will not develop the best spark energy to support the engine power levels no matter what fuel octane you use.