A little bit of pumice gel to blend them into the bases did the trick very quickly (as they were already painted), but I wanted the interiors to look a little nicer than just throwing some dirt in there.
For building number one, I used a slab of Imex on the left, with a few spare tiles cut out of plastic. On the left I used some textured paper to look like cobblestones. I think this piece needs a little more work on the floor, probably checkerboard tiles. They are cheesy, but they are effective.
Speaking of alternating tiles, the second building featured a second level sniper perch. Both the tiles and the cracked floor were made by carving into foam core with one side of the paper peeled off. It's a great alternative to carving pink/blue foam and I find it really easy to handle. A little bit of pumice gel to add interest really set this off.
Building number three features a wooden floor made out of popsicle sticks split in half and cut up. The mesh on the left was supposed to be old carpet, which I may still do by glazing it.
On the workbench are GZG Crusties and mechs, because I want to expand them as an OpForce. This is to take a run at Platoon Forward by Toofat Lardies, using Fubar rules. These ruins will feature heavily in this project too.
I have (of course) come up with a few new projects I'm excited about that will further stress my free time, but I'll post about them when I actually do work on them.
Thanks for looking!