Parts catalog here:
It's a great place to look for the small parts and "look through walls" so we don't have to climb under the beast?
If I'm following your directions on the dinette correctly, the parts shows a 12 volt outlet near the left side of the dinette table as we would stand in front of it and a bit lower than the table? Maybe a plug with rubber stopper cover?
Perhaps matching this drawing if we were looking down from standing in front of the table?
Outside item not shown in drawings.