Alright, so it was dry enough today to start detailing. I was using that white air dry compound, I think it's just white glue mixed with corn syrup, yeah next time I'd make my own if it wasn't so aggravating to work with. Could work ok as a filler though aluminum is cheaper and easier to use. Also lighter. Still, I used it because I still have some left, and also because I needed to give it a concrete-like finish, and this seems like it has a smooth texture. It will probably crack a bit on the surface as it shrinks, but that's cool. Also, it should absorb paint very well. A detail I forgot to mention is that I added a layer of thinned down white glue to the bare clay so that this would adhere properly.
The good thing is that experience and patience get you through this, so here are my results. I used styrofoam as a core, it protruded a bit in some places just under the surface, and any heat will basically melt it and leave a thin enough shell that you can break through and make a hole. The cracks appeared naturally on my unevenly humidified clay. Anyway, here it goes-
Overall it's a relatively heavy piece, but that styrofoam is going to serve as a base. Just need to dig into it a bit so it looks like it dug into the ground. Also have to make an adjacent fragment for the broken off cybernetic eye, with maybe a plan growing right next to it.