Cant tell in the pic, but are those wires for the light, or is that a folded down antenna behind the light?
anywho...
also looking at the pic, the pulpit would not be that good cuz of the anchor. running the wire through the rail would work like Grub says. Normally when i have to run cables in pipe, I tape a small screwdriver bit onto the end of the string, feed it into the pipe and use a strong magnet (wrapped in tape to keep from scratching the pipe) to pull the string to the end. It looks like your run would be pretty easy,just have to get it into the cabin. Not sure how you could do that without having the cable exit out of the pipe, then drill a hole into the cabin, or ifyou could unbolt thelast section, pull it out of the way, drill ahole in the bottom of the rail mount, then under the base drill a hole to feed the cable through. if the cable was external, you would only have to get a perko grommet to seal the hole.