You need the base plate, the tow bar, safety cables, electrical connections for the running lights and turn signals and brake lights, an auxiliary brake for the toad and a break away safety cable.
There is a wide variation of equipment and options to choose from.
2009 Holiday Rambler 42' Scepter with ISL 400 Cummins
750 Watts Solar Morningstar MPPT 60 Controller
2014 Grand Cherokee Overland
Bob