I have worked on these type of homes before. most of the time there is a 1" chase through the panel every 24" horizontally and every 48" vertically. I the assemblers of the panels line them up right you will at least be able to wire up each wall easilly and then move from wall to wall through the floor or the ceiling. a zip tool or jigsaw works well to cut the boxes out (which you may want to locate at 24" to the top) and I like to use plastic boxes with 'ears'. Wiring a house like this is a lot like doing a log home so I would make sure to account for the labor intensive aspects of cutting notches, boxes, etc. Good Luck!
