Well if you don't mind a bit of an overhaul, I came up with some of my own ideas. I thought the mid would be cool if the building was 2 story, with the old tunnel forming the lower floor. It would be functionally the same, but appear very different. The land could join up with the point either side as a bridge a la Badlands, to keep that functionality the same, and use crates or whatever to fill the gap between the displacements and the bridge. That means turning the displacements into a depression, which makes much more sense than a tunnel. Note also that this fixes the effect right now where the tunnel doesn't really look like it can support it's own weight. Lemme make up a picture:
Wow, if I keep messing around in paint I'll never get any revision done. Here, the red bit is the two story house. The triangle shape is a kind of balcony that runs either side that allows players to go past. In order to avoid having a steep drop half a meter from the walls of the house, which would look strange, the blue arrows represent a gentle decline in angle that forms a valley. In order for players to still access the house, a wooden walkway exists represented by the yellow which would continue off screen. In order to stop players accessing either side of the walls on the lower floor, crates and grates are represented by green that fill the area between the displacements and the wood above. Comprende?
Oh, and for the side tunnels between mid and second (and the last/second tunnel, if you still have it), just make them look like Dustbowls:
EDIT: Man, I put all this thought into the midpoint and I'm increasingly convinced it'll look stupid. Lemme get back to you on that. Maybe all you need is some foundation pillars in the tunnel and it'll look fine. In fact, that's basically the issue: This building has no foundations at all.