My drain line ran down & underneath the trailer. If you are running the drain line outside of the vent, as indicated, why can't you still use the line for the 12 volt connection ? Run the 12 volt through a small hole in the drain tubing further up from the opening & silicone the area of exit.
PS, My tubing had a splice in it just before it went down through the base of the frig area & underneath. I undid the splice, ran the wire out & then reconnected it. You could add a slice to yours & make it easier to get the wire through.
