[RUNNERBUN]

Hello Tom, thank you for your compliments. Yes I did convert my car to 12 volt. I agree with others that there is nothing wrong with 6 volt. 12v is just that much more convenient for running accessories such as GPS, 2 way Radio and in my case a 12v fridge as well.
Wiring trailer lights is a fairly straight forward procedure. You will need to break into your cars wiring harness at the Tail/brake light end and add an extension down to a standard trailer socket, trailer plugs and sockets normally come with wiring instructions for the correct sequence, you will have to do the same from your directional indicators if you have them fitted. Personally I wouldn't drive a car in todays traffic without directional indicators. Just to dangerous without them. We call them Orange Warts.
One more bit of advise is when selecting trailer lights go for the newer LED lights as they give a much stronger light during the day time. Not sure if 6 volt LED trailer lights are available.
All the best
Runner