i have not noticed any threads about the ladders in th map Dark cave or the cave areas in the water fall map. i will speak up for everyone when i say this: how do we use these, if at all possible?

I think it just doesn't work and you should just leave it
The map is from game freak pokemon games (pokemon white ,pokemon black,pokemon red ECT.)

they do work. i tried the caves in waterfall and it works.

so then why do none of the ladders work? or the doors? or the second cave in waterfall?

I don't know about the dark cave,but I think there is a condition to use these Icons.for example the safari zone has a locked door in the northern most of the map that will open if you travel to Fuchisa city

You can't use doors all they are is photos of the one in the games and nothing more ladders you can use maybe but the others are just decor

Doors and openings like the tents/teepees in Snowpoint Town do not work.
As for the ladders, some will work and others won't. It's just a matter of seeing for yourself.
If you use a ladder though, the chances of finding a certain Pokemon or any Pokemon does not change.