Ah, the single story does add a twist since nothing needs to penetrate
too far. Oh well.

A note regarding "fishing" through the probe holes. As I mentioned
earlier I used a heavy guage ground wire that I measured and marked
with tape at certain legths so I knew how far I was getting before
hitting an obstruction. I had tried to use a string with various
weighted objects attached including a plumb bob, but they are very
clumsy to move around. There may be a path for what you want to do,
it just might not be in an exact straight path, so using a wire or
real fish tape helps.

Good luck!