Hi,
You probably would need to find something really light, like a Scamp, or
ALiner.comThe problem is that the 4Runner is a heavy vehicle, with a limited GVWR, so the cargo rating is not huge. The engine is small. Transmission might not like working hard to push a lot of air out of the way. So if your curb weight is say 4,400 pounds and the GVWR is say 5,500 pounds, that leaves limited capacity, of 1,100 pounds for the hitch weight, passengers and any gear that you might want to carry inside the compact truck.
Good luck,
Fred.