The easiest way to figure out what you need is by looking at your RV/Camper. What can go wrong and how would you fix it?
I carry a set of sockets and some wrenches plus the above "normal" sizes for the 5th wheel hitch, etc. A multimeter, small tube of silicon, a tube of lap seal, a roll of seal (forget the name), some spray silicone and PB Blaster. A 4 way wrench for lugs, jack that was fine for the TT we had but may not work with the 5er (have to check that!), rubber mallet, camp hatchet, battery leaf blower, small screwdriver kit with multiple bits, battery op drill and some drill bits, spare water hose gaskets, fuses, electrical tape, duct tape, command strips/hooks and a damn good flashlight/work light. Air compressor and guage, and check your camper tires + the spare!
Pro tip: if you use a power tool to raise and lower your stabilizer jacks use a drill NOT a impact! Get the 1/4" to 3/8" adapter for the DRILL and use a socket, I think they are 3/4". Set the torque on the DRILL to just past snug on the jack.