I had to deal with the seam where the removable mountain ridge meets the plywood.

You may have noticed plastic along the perimeter of the mountain ridge in previous photos. I placed strips of plastic wrap along the base before I started building it. I taped the plastic wrap to the plywood in the area that would be covered by the ridge. I could have waited later in the process before installing the plastic wrap. I lifted the plastic wrap up towards the mountain. I used Sculptamold to create a built up area on the plywood surface along the perimeter of the ridge.

While I was working on this, I filled in the gaps behind the portal and retaining walls. I also had to improvise some separators out of plastic and tape where the modules touched each other. This would prevent the Sculptamold on touching modules from joining when it dried. I let the Sculptamold dry a few days before I continued.

Next, I pulled the plastic wrap over the built up area. I filled in the gap between the built up layer and the mountain ridge with Sculptamold. The plastic wrap will act as a separator preventing the wet Sculptamold from drying to the built up layer. I let this dry for a few days before continuing.

I removed the plastic wrap. I used a large file to smooth out the new seams along the mountain ridge and module joints. The seams are slightly visible. They should disappear more when I add scenery to it.

This shows what the area looks like with the mountain ridge removed. I will extend the Sculptamold coverage towards the front of the modules at a later date.