I carried Lucas fifth wheel grease but really only used it before I left out. I kept my trailer at an empty lot so I was greasing every week or two depending on how long I stayed out. I liked the Lucas product but it was much more loose than grease so it had potential to be sloppy if I didn’t use it sparingly.
I carried a couple gallons of premixed, spare belts, alternator, air regulator, one each of fuel filters (I have two), trailer air lines, glad hands and gaskets, tools, air hose for airing up tires, electrical tape, duct tape, solder and mini torch. That’s all I can think of right now.