Mine is a 2004 V8 Sport with the trailer package. I still use the Toyota trailer hitch that came on the 4Runner. I tow 2500 lb off road camping trailer with a Treg hitch in the standard 2" receiver.
I use the standard 2" hitch that slides into the receiver and is held in with a pin. Mine is about 2" drop configuration. Normaly you then bolt on a ball hitch.
For me since I need the off road articulation, I use what's called Treg hitch. Mine is from Austrailia. In the US there are similar off road hitches you can buy if that is what you are looking for.
For normal street use the standard ball hitch is fine.