For the legs I had in mind something like the tipods from War of the Worlds. While making the bockpit the polystyrene ball has been sat on a plastic ring. I cut slits into this so the 3 legs would slot in. The 3 legs fit snugly together and are packed out with hot glue.
To give a good surface texture the legs are painted white and then stained with burnt umber, this is rubbed back slightly with a soft paper towel to give a nice texture.
The legs are given detail with layers of card and bits of plastic to make pistons