Good morning! Here's a shot of my '06 OEM setup -- 2 12 volt batteries in parallel. The small wire coming off the near battery + pole goes to the tongue jack -- if you have one you want the tongue jack to work whether the master switch is turned on or off.
I am also trying to figure out how to wire my new AGM batteries. I'm adding a new battery rack and a new battery box, but the current cables won't reach the new position, and the battery connections are different from my standard battery that was currently installed. Any help would be appreciated. It looks like the other reply will work for connecting the batteries in series, but I still need to connect to the rest of the AS.