Welcome to the forum! You can't run a portable grill that uses disposable bottles on your trailer system WITHOUT MODIFICATION as the trailer pipeline is regulated to 11" water column and the portable grill has a high pressure regulator built into the control knob assembly. If you try to run the portable grill directly off the trailer pipeline there won't be enough pressure to get the grill regulator to operate thus no flame.
I run a portable grill that was originally designed for disposable cylinders off my trailer system. The way I did it was to fabricate a properly sized orifice into a throttling valve that screws into the burner venturi tube of the grill. There is a hose that connects from the throttling valve to the quick connect on the frame of the trailer.
There are charts on the internet that will give you the proper diameter orifice size for a given BTU output at a given pressure
2006 23B Hybrid with 10k round bar WDH
2011 F150 4x4 SCREW Ecoboost, Max Tow, Integrated TBC, 3.73 LS axle, Firestone Ride Rite airbags.