Class four/five hitch, 7 pin wire harness, good quality brake controller.
The hitch will need to be checked to be sure what you have. The brake controller can be what ever you want. Most people find that the better ones, Prodigy for instance are far superior in their actions.
When you get the trailer you will want some form of equalizer and possible a sway control.
After that the necessary items will be the same as the MH. Potable water hoses, sewer hoses, etc.
Don and Lorri
2007 Dodge 3500 dually