Well, for starters, I currently completely suck at “making things”… I tried making a wall section, exported the mesh to UE4, and applied the material that’s on the current cylinder rocks… and it looked like complete **** 
… I’m guessing I need to do more than a flat-ish wall with some lumps on it, but I have no idea what. I’m sure there’s something going on with mapping and resolution and all that, but I don’t see how to get the texture/material out of UE4 and into Blender (which also implies just unrolling the base mesh from the pillar won’t work either).
Part of why I want the rock from the UE4 content is, it’s just **** pretty and high quality. Most “free” models/mesh/etc I’ve been finding are really amateurish… if I wanted crappy looking, I’d do it myself 
Anyway, I hope someone knows how to do it, or knows where a good tutorial for doing it in Blender would be. I have about 30 things I’m ready to try (foot steps, transitioning from 3rd to 1st person, inventory, hud, weapons, and even bringing in a nice high quality mesh for the character), but most of it is pointless unless I have my starting cave to spawn in 