I don't get how to do this. Say I have an indoor generator farm indoors on the first floor and I want to run power up to the fourth floor. Logically it seems like the way would be to run power out through wall and up the exterior side of the building, but I can't figure out any way to do this. Is there any trick to accomplish this (other than the bug that leaves you with a permanent wire)?

Sometimes you can glitch it and run the cables through the wall. What you do is connect to conduits initially outside and then manually move one of them inside.

I used a half wall like a window but there has to be a better way.

Walls, no. The game is pretty strict on that. Roofs and floors, on the other hand, allow cables to clip through them.

There are walls and roofs with holes in the corners you can use those. http://postimg.org/image/qgah01c63/

Yup. I just bring them in through a window opening.

Ya you just have to pick a wall that has a small hole or crack in it then move things around till you get it.

Ah so that's why they made these pieces with so many holes in them.. there was a method to their madness. Now if only I could get rid of the half broken houses in some settlements and start with a fresh concrete foundation.

Use combinations of the 3 conduits (sideways/upside down/upright) to get cables around and along places. Take wires along the outside (along walls and under floors) using these, and if you really need you can bring them through gaps as well same way. Get wires to buildings far away from generators using the little poles to keep them off the ground.

You do know that you can do exactly that, right? The demolished houses in Sanctuary, for example, can be completely scrapped in workshop mode; viola, your fresh concrete slab, made to order.