So, here's piles of the various stuff:
In this shot, I've stacked 1x1's, half tiles, more 1x1's, and then I've snapped some 2x1's along their creases so I can spread them out on my gapped grid!
Here's a bucket load more tiles!
And some cavern scenery pieces - like crates, stalagmites, etc
I've started work on some pieces, to get a feel for how I want to assemble the dungeon tiles:
To begin with, I laid out the pieces - a mix of 1x1's and snapped 2x1's, and a 'hole' in the middle with some wooden planks over it.
Then I glued down the stonework.
Then I painted textured paint into the gaps between the tiles, and around the 'hole' in the middle.
While it was still wet, I glued the planks down, pressing them into the textured paint on either side. I stuck them at slightly odd angles, for interest.
Here's a sorcerer for scale. The gapping means that figures aren't base-to-base touching, so larger figures, or poses with weapons jutting out, etc, can all fit together on the grid.
Plaster takes paint a little differently to how plastic or metal does - the outer layer of the plaster absorbs the pigment. To paint it up, you need to water down the paint, so you can easily spread it around and get it into the cracks and details. I mixed two parts of my medium grey (the one I got from the hardware store ages back in a tin) with one part of water, in an empty paint pot, shook it up, then used a wash brush to give an undercoat to the whole piece.