Forgot to mention.. For charge line you will want to add a relay which will only energize the charge line when the engine is running or ignition key is turned on.
This prevents your trailer from discharging the vehicle battery when you are stopped..
You can take a look at a diagram I made on page 41 of my following pdf document..
HEREDisclaimer.. I have had issues with this link dying off if I get logged out.. additionally google makes you use their pdf viewer which messes with photos.. You can download the PDF and use Adobe viewer to see the pictures correctly..