My plan was to run a miniUSB cable from the windshield mounted dashcam, under the headliner, under the door trim and to a switched socket in the primary fuse block.
It worked perfectly.
I found a miniUSB cable that had the proper angle to fit flat against the windshield and leave the dashcam headed directly to the top of the windshield. The headliner was loose enough to slide the cable under it.
When I got the to driver's A pillar, I was able to slip the cable into the gap between the trim and the windshield. I snaked it down to the top of the dash and moved it over to the soft rubber door jamb trim. I slipped the cable under the trim and ran it down to the bottom of the dash.
I put an Add-A-Circuit in the rightmost middle fuse socket. In my 2013 Accord this socket is switched with the ignition. I put the 10A fuse displaced from the fuse socket into the primary socket of the Add-A-Circuit and put a 7.5A fuse (included with the Add-A-Circuit) in the additional fuse socket of the Add-A-Circuit.
I attached one wire from the socket to the Add-A-Circuit with a wire nut and the other end to a convenient ground screw.
I grabbed a spare USB car outlet adapter from my junk drawer and inserted it into the car outlet adapter socket. Then I plugged the miniUSB cable into it.
I should have zip tied all this together and velcroed it under the dash. I didn't. There wasn't much spare cable left so I just slipped the car outlet adapter socket up under the edge of dash. It seemed secure and has been there every since.
Here's what it looks like.
I slipped this up under the edge of dash.