Plumb in a propane quick connect ?

If you can access the black gas pipe under your trailer, it's not a tough job to cut in, thread pipe and install a tee. Other option is an Extend-A-Flow kit like I used on my old trailer to take gas directly off the tanks.

If you do tee off your propane line, put in a valve or petcock before the quick connect. That way, when the line isn't in use, you have additional assurance against leaks.