I just carry a quick detailer (griots speed shine or onr diluted) and some ultra plush mf towels. If you want to make a kit out of it, maybe carry a little KAIO in a little squeeze bottle and a foam pad, since it's a chemical polish.
Other than that, you should just bring the car back to home base to really correct any etching.
I personally feel that if your car is already protected with klasse twins and wax, you just need the qd and mf cloths in the trunk.
I attempted to make a travel kit, and during the first hot day, my little bottle of speed shine seeped out into the battery compartment. Need to rethink my kit, bit I definitely want to be traveling with one