Getting into the Substance Designer game. Still a newbie and my results are absolutely not without flaws. I appreciate Ben Wilson for his fantastic tutorial in which he describes his steps and thinking process very clearly. https://gumroad.com/l/OTAHK
For the cave I made an irregular tube shape in Zbrush by taking a cube and deforming it (stretching, twisting, applying random noise at a low threshold) then smoothing out select areas, ZRemeshing it, UVing, and applying the texture and tiling it at an appropriate rate. It's not perfect but it's a super fast way of making an entire cave. The tessellated mesh could be decimated to a more appropriate polycount and made game-ready.