Oh man, what I would have given for a time machine today...
Back when I built my vertical stabilizer, I never thought I'd want to install a tail camera -- so I never installed a conduit, or ran extra wire through the structure. Today, I spent an inordinate amount of time correcting that situation. I temporarily removed the VOR/LOC/GS antenna puck and slightly widened the existing opening at the forward end of the top rib, then fed a 5/8" plastic tube through the stabilizer, all the way down to the bottom rib. This involved making a hook out of a coat hanger, inserting a tiny flashlight in the other available hole in the rib, and fishing around by feel until I hooked the tubing. I then maneuvered it down slowly, inch by inch, until I could grab it with a pair of needle-nosed pliers. I secured the tube at the top end with Goop adhesive, and once it dries I'll stretch the tube and secure it at the bottom end with more Goop. I'm hoping this will prevent it from shifting too much when in operation. I may have to Goop it along its length, too.