I picked up a few more parts for the car today.
I bought a 12 gauge, 25 foot extension cable to run from the wall to the charger.
I got a "marine Charger Plug", which is a waterproof connection to a 15-amp male power connector. I am planning to put this where the gas cap would have gone. I believe this is the EXACT same part as where you plug in on a
ZENN
I also got a GFI outlet. I will put this in a box and run the charger power through it. My garage does NOT have a GFI outlet in it. Even out of the rain, it's always damp in there. There is also the possibility of the car opportunity charging at someone's older home which does not have a GFI exterior power outlet.
I am still planning on using Romex household wiring for the plug on the charger itself, as this is the cheapest, most heavy-duty cabling I can find. (Also, I already have some!) I don't think I want to run a long line of it in the car, as I have heard that solid wiring doesn't deal with vibration as well as stranded does.