If you ask 100 bike tourists what they use for chain lube you will get at least 150 different answers.
Now for my answer, I used to use petroleum based lubes that were dust magnets. Quit doing that. I think the last tour I used a petroleum based oil lube was the tour when I took this photo.
Now I use Finish Line Ceramic Wax, dry version. Once or twice a week I would crank the crankset with a paper towel held on the chain. The lube was not a magnet for grime, almost no buildup of dirt. I would lube it when it sounded noisy. And carried my lube in my handlebar bag so it only took seconds to get to it. If your lube is in the bottom of a pannier, you will forget to use it when you finally get to the campsite later. (Yes,this photo is of a different bike.)
Carry some disposable medical gloves for things like bike maint and repair. I regularly use soap and water to wash my disposable gloves while I am still wearing them to clean them for re-use. I only discard them once a hole develops. For a cross country ride, I might bring between a half dozen to a dozen pairs of those gloves, they easily puncture and tear.