I chose to avoid the fuse box, since it was too complicated. Instead, I bought some USB mini cables and made a reversible splice into the center console USB power line. This gives my dashcam a switched, 5V supply. I don't know if this has enough power for more than USB devices, though. I routed the dashcam USB cable through the dashboard and up the right side a-pillar (watch out not to block the airbag) to reach the camera.
I used Molex Part Number: 111015-0200 (USB mini B plug, polarization A, to USB A receptacle), and
Molex Part Number: 111019-2010 (USB mini B plug to USB mini B receptacle, polarization A).
I had to cut the keyways into the USB mini B parts, but other than that, it was fairly straightforward.
