Big update! Finally got a few things accomplished the last few days. I drilled a hole in the bottom corner of the mountain to fit the cord for the LED lights from the tunnel, and ran the cord up into the ceiling of the Dinobot cave.
Once that was done, I spray painted some larger stalactites:
I then glued them to the ceiling of the Dinobot cave. Once that dried, I put the pieces of the cave interior into place and put the ceiling part in last. The roughly finished cave:
I still have to put a few small pieces in as filler in 2 spots close to the ceiling, as well as spray paint the cave floor with the same ground texture paint as the outside. I also may paint the exposed bones with a slightly white dry brush, since they are a little more yellow than I wanted. I think a little white may help them pop a bit more on the rock background. Grapple and Wheeljack decided to inspect the cave for dimension and scale:
I still have to paint the exterior of the cave and side of the mountain yet. Maybe next weekend. Once I had the cave put together, I turned my attention to the background. I made another run to the hardware store and picked up a 4'X8' sheet of 1/8" thick rigid backing board for $8 that they cut into 3 pieces.