I created a Staircase, that you can use in combination with my elevated tiles (https://www.thingiverse.com/thing:3523328) if you prever those over ladders. The Staircase is quite small to fit as a 2x2 tile, but at least one mini should be able to stand on the middle level. As the rest of the things I remixed and designed, those are made to fit on any 2x2 openforge 2.0 bases. Keep in mind that you'll need to mirror the stairs in your slicer software, if you want the left oriented version. I designed the corpus myself, but I used Lifeburns Cavern Wall and Floor Textures on it, to make it fit perfectly between other cavern tiles.
IMPORTANT: Print the Version "wfloor" if you want to use the stairs on the ground level, otherwise you will have a gap on the floor. Print the ones without floor "plain" to use on top of other elevated tiles to create even higher Plateaus. (Those don't require a base obviously, unless you're planning on using bases between the higher levels-which might look a little awkward).
EDIT: I added the straight single and double versions of the stairs if you prefer those. As above each have a version "wfloor" and plain.
If you liked these, check out my other remixes. I made a lot of Lifeburns Dungeon Tiles Openforge 2.0 compatible:
the cavern tiles https://www.thingiverse.com/thing:3516425
the cavern river tiles https://www.thingiverse.com/thing:3517355
the cavern passage https://www.thingiverse.com/thing:3520357
the cavern elevated tiles https://www.thingiverse.com/thing:3523328
the cavern pillars https://www.thingiverse.com/thing:3523505
the graveyard tiles https://www.thingiverse.com/thing:3518744