What does one do about chain maintenance on a long tour?
a little chain lube every once in a while , then put a new chain on before the next tour.
running it thru a rag to knock off dirt , is OK the roller bushing and pin surfaces is all that really need the Lubrication.
& I've run kind of retro simple drive train bikes on my tours .. 3 by 6 not 9 speed or 10 .