With this in mind I have in the last week or so begun designing and then making some cavern corridors. These are slimmer than the original corridors or the forest paths I have made.
So far I have made only one of each to see how to make them and get an idea of how they look.
This set up was on a bit of an uneven surface, but you get the idea. Next stage will be mass production.... well 2 of everything and 5 or so of the straight